diff --git a/src/apps/deskflow-client/MSWindowsClientTaskBarReceiver.cpp b/src/apps/deskflow-client/MSWindowsClientTaskBarReceiver.cpp
index b09a93be8..b3fbf2ac8 100644
--- a/src/apps/deskflow-client/MSWindowsClientTaskBarReceiver.cpp
+++ b/src/apps/deskflow-client/MSWindowsClientTaskBarReceiver.cpp
@@ -211,7 +211,7 @@ void MSWindowsClientTaskBarReceiver::copyLog() const
 {
   if (m_logBuffer != NULL) {
     // collect log buffer
-    String data;
+    std::string data;
     for (BufferedLogOutputter::const_iterator index = m_logBuffer->begin(); index != m_logBuffer->end(); ++index) {
       data += *index;
       data += "\n";
diff --git a/src/apps/deskflow-server/MSWindowsServerTaskBarReceiver.cpp b/src/apps/deskflow-server/MSWindowsServerTaskBarReceiver.cpp
index eb6ee5c0d..b42926683 100644
--- a/src/apps/deskflow-server/MSWindowsServerTaskBarReceiver.cpp
+++ b/src/apps/deskflow-server/MSWindowsServerTaskBarReceiver.cpp
@@ -238,7 +238,7 @@ void MSWindowsServerTaskBarReceiver::copyLog() const
 {
   if (m_logBuffer != NULL) {
     // collect log buffer
-    String data;
+    std::string data;
     for (BufferedLogOutputter::const_iterator index = m_logBuffer->begin(); index != m_logBuffer->end(); ++index) {
       data += *index;
       data += "\n";
diff --git a/src/lib/arch/IArchDaemon.h b/src/lib/arch/IArchDaemon.h
index 4c9ccf115..22b06d927 100644
--- a/src/lib/arch/IArchDaemon.h
+++ b/src/lib/arch/IArchDaemon.h
@@ -18,8 +18,8 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/IInterface.h"
+#include <string>
 
 //! Interface for architecture dependent daemonizing
 /*!
diff --git a/src/lib/arch/IArchFile.h b/src/lib/arch/IArchFile.h
index 80f63651d..c7b3563da 100644
--- a/src/lib/arch/IArchFile.h
+++ b/src/lib/arch/IArchFile.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/IInterface.h"
 #include "common/stdstring.h"
 
@@ -93,12 +92,12 @@ public:
   /*
   Returns the user's profile directory.
   */
-  virtual void setProfileDirectory(const String &s) = 0;
+  virtual void setProfileDirectory(const std::string &s) = 0;
 
   //@}
   //! Set the user's plugin directory
   /*
   Returns the user's plugin directory.
   */
-  virtual void setPluginDirectory(const String &s) = 0;
+  virtual void setPluginDirectory(const std::string &s) = 0;
 };
diff --git a/src/lib/arch/IArchTaskBarReceiver.h b/src/lib/arch/IArchTaskBarReceiver.h
index 903da8f5e..59a1c5e81 100644
--- a/src/lib/arch/IArchTaskBarReceiver.h
+++ b/src/lib/arch/IArchTaskBarReceiver.h
@@ -18,9 +18,10 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/IInterface.h"
 
+#include <string>
+
 class IScreen;
 class INode;
 
@@ -91,7 +92,7 @@ public:
   */
   virtual std::string getToolTip() const = 0;
 
-  virtual void updateStatus(INode *, const String &errorMsg) = 0;
+  virtual void updateStatus(INode *, const std::string &errorMsg) = 0;
 
   virtual void cleanup()
   {
diff --git a/src/lib/arch/unix/ArchFileUnix.cpp b/src/lib/arch/unix/ArchFileUnix.cpp
index 0f04336e0..3644e2a5e 100644
--- a/src/lib/arch/unix/ArchFileUnix.cpp
+++ b/src/lib/arch/unix/ArchFileUnix.cpp
@@ -146,12 +146,12 @@ std::string ArchFileUnix::concatPath(const std::string &prefix, const std::strin
   return path;
 }
 
-void ArchFileUnix::setProfileDirectory(const String &s)
+void ArchFileUnix::setProfileDirectory(const std::string &s)
 {
   m_profileDirectory = s;
 }
 
-void ArchFileUnix::setPluginDirectory(const String &s)
+void ArchFileUnix::setPluginDirectory(const std::string &s)
 {
   m_pluginDirectory = s;
 }
diff --git a/src/lib/arch/unix/ArchFileUnix.h b/src/lib/arch/unix/ArchFileUnix.h
index d30f5f846..fa684cf28 100644
--- a/src/lib/arch/unix/ArchFileUnix.h
+++ b/src/lib/arch/unix/ArchFileUnix.h
@@ -38,10 +38,10 @@ public:
   virtual std::string getPluginDirectory();
   virtual std::string getProfileDirectory();
   virtual std::string concatPath(const std::string &prefix, const std::string &suffix);
-  virtual void setProfileDirectory(const String &s);
-  virtual void setPluginDirectory(const String &s);
+  virtual void setProfileDirectory(const std::string &s);
+  virtual void setPluginDirectory(const std::string &s);
 
 private:
-  String m_profileDirectory;
-  String m_pluginDirectory;
+  std::string m_profileDirectory;
+  std::string m_pluginDirectory;
 };
diff --git a/src/lib/arch/win32/ArchFileWindows.cpp b/src/lib/arch/win32/ArchFileWindows.cpp
index fef30154b..d6706ba31 100644
--- a/src/lib/arch/win32/ArchFileWindows.cpp
+++ b/src/lib/arch/win32/ArchFileWindows.cpp
@@ -143,7 +143,7 @@ std::string ArchFileWindows::getPluginDirectory()
 
 std::string ArchFileWindows::getProfileDirectory()
 {
-  String dir;
+  std::string dir;
   if (!m_profileDirectory.empty()) {
     dir = m_profileDirectory;
   } else {
@@ -173,12 +173,12 @@ std::string ArchFileWindows::concatPath(const std::string &prefix, const std::st
   return path;
 }
 
-void ArchFileWindows::setProfileDirectory(const String &s)
+void ArchFileWindows::setProfileDirectory(const std::string &s)
 {
   m_profileDirectory = s;
 }
 
-void ArchFileWindows::setPluginDirectory(const String &s)
+void ArchFileWindows::setPluginDirectory(const std::string &s)
 {
   m_pluginDirectory = s;
 }
diff --git a/src/lib/arch/win32/ArchFileWindows.h b/src/lib/arch/win32/ArchFileWindows.h
index ff1ed8d31..61ceba52f 100644
--- a/src/lib/arch/win32/ArchFileWindows.h
+++ b/src/lib/arch/win32/ArchFileWindows.h
@@ -38,10 +38,10 @@ public:
   virtual std::string getPluginDirectory();
   virtual std::string getProfileDirectory();
   virtual std::string concatPath(const std::string &prefix, const std::string &suffix);
-  virtual void setProfileDirectory(const String &s);
-  virtual void setPluginDirectory(const String &s);
+  virtual void setProfileDirectory(const std::string &s);
+  virtual void setPluginDirectory(const std::string &s);
 
 private:
-  String m_profileDirectory;
-  String m_pluginDirectory;
+  std::string m_profileDirectory;
+  std::string m_pluginDirectory;
 };
diff --git a/src/lib/arch/win32/ArchMiscWindows.cpp b/src/lib/arch/win32/ArchMiscWindows.cpp
index 59a1f8b81..c06ae6cfd 100644
--- a/src/lib/arch/win32/ArchMiscWindows.cpp
+++ b/src/lib/arch/win32/ArchMiscWindows.cpp
@@ -384,7 +384,7 @@ void ArchMiscWindows::wakeupDisplay()
 
 bool ArchMiscWindows::wasLaunchedAsService()
 {
-  String name;
+  std::string name;
   if (!getParentProcessName(name)) {
     LOG((CLOG_ERR "cannot determine if process was launched as service"));
     return false;
@@ -393,7 +393,7 @@ bool ArchMiscWindows::wasLaunchedAsService()
   return (name == SERVICE_LAUNCHER);
 }
 
-bool ArchMiscWindows::getParentProcessName(String &name)
+bool ArchMiscWindows::getParentProcessName(std::string &name)
 {
   PROCESSENTRY32 parentEntry;
   if (!getParentProcessEntry(parentEntry)) {
diff --git a/src/lib/arch/win32/ArchMiscWindows.h b/src/lib/arch/win32/ArchMiscWindows.h
index e9800aafc..abb3b7b31 100644
--- a/src/lib/arch/win32/ArchMiscWindows.h
+++ b/src/lib/arch/win32/ArchMiscWindows.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdset.h"
 #include "common/stdstring.h"
 
@@ -164,7 +163,7 @@ public:
   static bool wasLaunchedAsService();
 
   //! Returns true if we got the parent process name.
-  static bool getParentProcessName(String &name);
+  static bool getParentProcessName(std::string &name);
 
   static HINSTANCE instanceWin32();
 
diff --git a/src/lib/base/EventQueue.cpp b/src/lib/base/EventQueue.cpp
index fa9df6f3d..3ba9c6bf6 100644
--- a/src/lib/base/EventQueue.cpp
+++ b/src/lib/base/EventQueue.cpp
@@ -510,7 +510,7 @@ double EventQueue::getNextTimerTimeout() const
   return m_timerQueue.top();
 }
 
-Event::Type EventQueue::getRegisteredType(const String &name) const
+Event::Type EventQueue::getRegisteredType(const std::string &name) const
 {
   NameMap::const_iterator found = m_nameMap.find(name);
   if (found != m_nameMap.end())
diff --git a/src/lib/base/EventQueue.h b/src/lib/base/EventQueue.h
index 309a60152..84a95923b 100644
--- a/src/lib/base/EventQueue.h
+++ b/src/lib/base/EventQueue.h
@@ -63,7 +63,7 @@ public:
   virtual bool isEmpty() const;
   virtual IEventJob *getHandler(Event::Type type, void *target) const;
   virtual const char *getTypeName(Event::Type type);
-  virtual Event::Type getRegisteredType(const String &name) const;
+  virtual Event::Type getRegisteredType(const std::string &name) const;
   void *getSystemTarget();
   virtual void waitForReady() const;
 
@@ -107,7 +107,7 @@ private:
   using EventTable = std::map<UInt32, Event>;
   using EventIDList = std::vector<UInt32>;
   using TypeMap = std::map<Event::Type, const char *>;
-  using NameMap = std::map<String, Event::Type>;
+  using NameMap = std::map<std::string, Event::Type>;
   using TypeHandlerTable = std::map<Event::Type, IEventJob *>;
   using HandlerTable = std::map<void *, TypeHandlerTable>;
 
diff --git a/src/lib/base/IEventQueue.h b/src/lib/base/IEventQueue.h
index 8175cd273..6c8147c25 100644
--- a/src/lib/base/IEventQueue.h
+++ b/src/lib/base/IEventQueue.h
@@ -19,8 +19,8 @@
 #pragma once
 
 #include "base/Event.h"
-#include "base/String.h"
 #include "common/IInterface.h"
+#include <string>
 
 class IEventJob;
 class IEventQueueBuffer;
@@ -211,7 +211,7 @@ public:
   /*!
   Returns the registered type for an event for a given name.
   */
-  virtual Event::Type getRegisteredType(const String &name) const = 0;
+  virtual Event::Type getRegisteredType(const std::string &name) const = 0;
 
   //! Get the system event type target
   /*!
diff --git a/src/lib/base/Path.cpp b/src/lib/base/Path.cpp
index b3d812fbb..efc4b8deb 100644
--- a/src/lib/base/Path.cpp
+++ b/src/lib/base/Path.cpp
@@ -26,7 +26,7 @@ namespace filesystem {
 
 #ifdef SYSAPI_WIN32
 
-std::wstring path(const String &filePath)
+std::wstring path(const std::string &filePath)
 {
   std::wstring result;
 
@@ -40,7 +40,7 @@ std::wstring path(const String &filePath)
 }
 
 #else
-std::string path(const String &filePath)
+std::string path(const std::string &filePath)
 {
   return filePath;
 }
diff --git a/src/lib/base/Path.h b/src/lib/base/Path.h
index 45f1bad9f..4925c3135 100644
--- a/src/lib/base/Path.h
+++ b/src/lib/base/Path.h
@@ -16,16 +16,17 @@
  */
 #pragma once
 
-#include "String.h"
+#include <common/common.h>
+#include <string>
 
 namespace deskflow {
 
 namespace filesystem {
 
 #ifdef SYSAPI_WIN32
-std::wstring path(const String &filePath);
+std::wstring path(const std::string &filePath);
 #else
-std::string path(const String &filePath);
+std::string path(const std::string &filePath);
 #endif
 
 } // namespace filesystem
diff --git a/src/lib/base/String.cpp b/src/lib/base/String.cpp
index 9b73883f1..003071ca5 100644
--- a/src/lib/base/String.cpp
+++ b/src/lib/base/String.cpp
@@ -30,20 +30,21 @@
 #include <iomanip>
 #include <sstream>
 #include <stdio.h>
+#include <string>
 
 namespace deskflow {
 namespace string {
 
-String format(const char *fmt, ...)
+std::string format(const char *fmt, ...)
 {
   va_list args;
   va_start(args, fmt);
-  String result = vformat(fmt, args);
+  std::string result = vformat(fmt, args);
   va_end(args);
   return result;
 }
 
-String vformat(const char *fmt, va_list args)
+std::string vformat(const char *fmt, va_list args)
 {
   // find highest indexed substitution and the locations of substitutions
   std::vector<size_t> pos;
@@ -108,7 +109,7 @@ String vformat(const char *fmt, va_list args)
   }
 
   // substitute
-  String result;
+  std::string result;
   result.reserve(resultLength);
   size_t src = 0;
   for (int i = 0; i < n; ++i) {
@@ -121,12 +122,12 @@ String vformat(const char *fmt, va_list args)
   return result;
 }
 
-String sprintf(const char *fmt, ...)
+std::string sprintf(const char *fmt, ...)
 {
   char tmp[1024];
   char *buffer = tmp;
   int len = (int)(sizeof(tmp) / sizeof(tmp[0]));
-  String result;
+  std::string result;
   while (buffer != NULL) {
     // try printing into the buffer
     va_list args;
@@ -156,27 +157,27 @@ String sprintf(const char *fmt, ...)
   return result;
 }
 
-void findReplaceAll(String &subject, const String &find, const String &replace)
+void findReplaceAll(std::string &subject, const std::string &find, const std::string &replace)
 {
   size_t pos = 0;
-  while ((pos = subject.find(find, pos)) != String::npos) {
+  while ((pos = subject.find(find, pos)) != std::string::npos) {
     subject.replace(pos, find.length(), replace);
     pos += replace.length();
   }
 }
 
-String removeFileExt(String filename)
+std::string removeFileExt(std::string filename)
 {
   size_t dot = filename.find_last_of('.');
 
-  if (dot == String::npos) {
+  if (dot == std::string::npos) {
     return filename;
   }
 
   return filename.substr(0, dot);
 }
 
-void toHex(String &subject, int width, const char fill)
+void toHex(std::string &subject, int width, const char fill)
 {
   std::stringstream ss;
   ss << std::hex;
@@ -187,24 +188,24 @@ void toHex(String &subject, int width, const char fill)
   subject = ss.str();
 }
 
-void uppercase(String &subject)
+void uppercase(std::string &subject)
 {
   std::transform(subject.begin(), subject.end(), subject.begin(), ::toupper);
 }
 
-void removeChar(String &subject, const char c)
+void removeChar(std::string &subject, const char c)
 {
   subject.erase(std::remove(subject.begin(), subject.end(), c), subject.end());
 }
 
-String sizeTypeToString(size_t n)
+std::string sizeTypeToString(size_t n)
 {
   std::stringstream ss;
   ss << n;
   return ss.str();
 }
 
-size_t stringToSizeType(String string)
+size_t stringToSizeType(std::string string)
 {
   std::istringstream iss(string);
   size_t value;
@@ -212,13 +213,13 @@ size_t stringToSizeType(String string)
   return value;
 }
 
-std::vector<String> splitString(String string, const char c)
+std::vector<std::string> splitString(std::string string, const char c)
 {
-  std::vector<String> results;
+  std::vector<std::string> results;
 
   size_t head = 0;
   size_t separator = string.find(c);
-  while (separator != String::npos) {
+  while (separator != std::string::npos) {
     if (head != separator) {
       results.push_back(string.substr(head, separator - head));
     }
@@ -237,31 +238,31 @@ std::vector<String> splitString(String string, const char c)
 // CaselessCmp
 //
 
-bool CaselessCmp::cmpEqual(const String::value_type &a, const String::value_type &b)
+bool CaselessCmp::operator()(const std::string &a, const std::string &b) const
 {
-  // should use std::tolower but not in all versions of libstdc++ have it
-  return tolower(a) == tolower(b);
+  return less(a, b);
 }
 
-bool CaselessCmp::cmpLess(const String::value_type &a, const String::value_type &b)
+bool CaselessCmp::less(const std::string &a, const std::string &b)
+{
+  return std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end(), &deskflow::string::CaselessCmp::cmpLess);
+}
+
+bool CaselessCmp::equal(const std::string &a, const std::string &b)
+{
+  return !(less(a, b) || less(b, a));
+}
+
+bool CaselessCmp::cmpLess(const std::string::value_type &a, const std::string::value_type &b)
 {
   // should use std::tolower but not in all versions of libstdc++ have it
   return tolower(a) < tolower(b);
 }
 
-bool CaselessCmp::less(const String &a, const String &b)
+bool CaselessCmp::cmpEqual(const std::string::value_type &a, const std::string::value_type &b)
 {
-  return std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end(), &deskflow::string::CaselessCmp::cmpLess);
-}
-
-bool CaselessCmp::equal(const String &a, const String &b)
-{
-  return !(less(a, b) || less(b, a));
-}
-
-bool CaselessCmp::operator()(const String &a, const String &b) const
-{
-  return less(a, b);
+  // should use std::tolower but not in all versions of libstdc++ have it
+  return tolower(a) == tolower(b);
 }
 
 } // namespace string
diff --git a/src/lib/base/String.h b/src/lib/base/String.h
index 6bd53f41a..f38fdf3ee 100644
--- a/src/lib/base/String.h
+++ b/src/lib/base/String.h
@@ -24,12 +24,9 @@
 #include <stdarg.h>
 #include <vector>
 
-// use standard C++ string class for our string class
-using String = std::string;
-
 namespace deskflow {
 
-//! String utilities
+//! std::string utilities
 /*!
 Provides functions for string manipulation.
 */
@@ -45,67 +42,67 @@ characters and conversion specifications introduced by `\%':
 All arguments in the variable list are const char*.  Positional
 elements are indexed from 1.
 */
-String format(const char *fmt, ...);
+std::string format(const char *fmt, ...);
 
 //! Format positional arguments
 /*!
 Same as format() except takes va_list.
 */
-String vformat(const char *fmt, va_list);
+std::string vformat(const char *fmt, va_list);
 
 //! Print a string using sprintf-style formatting
 /*!
 Equivalent to sprintf() except the result is returned as a String.
 */
-String sprintf(const char *fmt, ...);
+std::string sprintf(const char *fmt, ...);
 
 //! Find and replace all
 /*!
 Finds \c find inside \c subject and replaces it with \c replace
 */
-void findReplaceAll(String &subject, const String &find, const String &replace);
+void findReplaceAll(std::string &subject, const std::string &find, const std::string &replace);
 
 //! Remove file extension
 /*!
 Finds the last dot and remove all characters from the dot to the end
 */
-String removeFileExt(String filename);
+std::string removeFileExt(std::string filename);
 
 //! Convert into hexdecimal
 /*!
 Convert each character in \c subject into hexdecimal form with \c width
 */
-void toHex(String &subject, int width, const char fill = '0');
+void toHex(std::string &subject, int width, const char fill = '0');
 
 //! Convert to all uppercase
 /*!
 Convert each character in \c subject to uppercase
 */
-void uppercase(String &subject);
+void uppercase(std::string &subject);
 
 //! Remove all specific char in suject
 /*!
 Remove all specific \c c in \c suject
 */
-void removeChar(String &subject, const char c);
+void removeChar(std::string &subject, const char c);
 
 //! Convert a size type to a string
 /*!
 Convert an size type to a string
 */
-String sizeTypeToString(size_t n);
+std::string sizeTypeToString(size_t n);
 
 //! Convert a string to a size type
 /*!
 Convert an a \c string to an size type
 */
-size_t stringToSizeType(String string);
+size_t stringToSizeType(std::string string);
 
 //! Split a string into substrings
 /*!
 Split a \c string that separated by a \c c into substrings
 */
-std::vector<String> splitString(String string, const char c);
+std::vector<std::string> splitString(std::string string, const char c);
 
 //! Case-insensitive comparisons
 /*!
@@ -115,19 +112,19 @@ class CaselessCmp
 {
 public:
   //! Same as less()
-  bool operator()(const String &a, const String &b) const;
+  bool operator()(const std::string &a, const std::string &b) const;
 
   //! Returns true iff \c a is lexicographically less than \c b
-  static bool less(const String &a, const String &b);
+  static bool less(const std::string &a, const std::string &b);
 
   //! Returns true iff \c a is lexicographically equal to \c b
-  static bool equal(const String &a, const String &b);
+  static bool equal(const std::string &a, const std::string &b);
 
   //! Returns true iff \c a is lexicographically less than \c b
-  static bool cmpLess(const String::value_type &a, const String::value_type &b);
+  static bool cmpLess(const std::string::value_type &a, const std::string::value_type &b);
 
   //! Returns true iff \c a is lexicographically equal to \c b
-  static bool cmpEqual(const String::value_type &a, const String::value_type &b);
+  static bool cmpEqual(const std::string::value_type &a, const std::string::value_type &b);
 };
 
 } // namespace string
diff --git a/src/lib/base/Unicode.cpp b/src/lib/base/Unicode.cpp
index 15acd8530..ec200dc17 100644
--- a/src/lib/base/Unicode.cpp
+++ b/src/lib/base/Unicode.cpp
@@ -84,7 +84,7 @@ inline static void setError(bool *errors)
 UInt32 Unicode::s_invalid = 0x0000ffff;
 UInt32 Unicode::s_replacement = 0x0000fffd;
 
-bool Unicode::isUTF8(const String &src)
+bool Unicode::isUTF8(const std::string &src)
 {
   // convert and test each character
   const UInt8 *data = reinterpret_cast<const UInt8 *>(src.c_str());
@@ -96,14 +96,14 @@ bool Unicode::isUTF8(const String &src)
   return true;
 }
 
-String Unicode::UTF8ToUCS2(const String &src, bool *errors)
+std::string Unicode::UTF8ToUCS2(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
 
   // get size of input string and reserve some space in output
   UInt32 n = (UInt32)src.size();
-  String dst;
+  std::string dst;
   dst.reserve(2 * n);
 
   // convert each character
@@ -123,14 +123,14 @@ String Unicode::UTF8ToUCS2(const String &src, bool *errors)
   return dst;
 }
 
-String Unicode::UTF8ToUCS4(const String &src, bool *errors)
+std::string Unicode::UTF8ToUCS4(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
 
   // get size of input string and reserve some space in output
   UInt32 n = (UInt32)src.size();
-  String dst;
+  std::string dst;
   dst.reserve(4 * n);
 
   // convert each character
@@ -146,14 +146,14 @@ String Unicode::UTF8ToUCS4(const String &src, bool *errors)
   return dst;
 }
 
-String Unicode::UTF8ToUTF16(const String &src, bool *errors)
+std::string Unicode::UTF8ToUTF16(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
 
   // get size of input string and reserve some space in output
   UInt32 n = (UInt32)src.size();
-  String dst;
+  std::string dst;
   dst.reserve(2 * n);
 
   // convert each character
@@ -181,14 +181,14 @@ String Unicode::UTF8ToUTF16(const String &src, bool *errors)
   return dst;
 }
 
-String Unicode::UTF8ToUTF32(const String &src, bool *errors)
+std::string Unicode::UTF8ToUTF32(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
 
   // get size of input string and reserve some space in output
   UInt32 n = (UInt32)src.size();
-  String dst;
+  std::string dst;
   dst.reserve(4 * n);
 
   // convert each character
@@ -207,7 +207,7 @@ String Unicode::UTF8ToUTF32(const String &src, bool *errors)
   return dst;
 }
 
-String Unicode::UTF8ToText(const String &src, bool *errors)
+std::string Unicode::UTF8ToText(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
@@ -220,7 +220,7 @@ String Unicode::UTF8ToText(const String &src, bool *errors)
   int len = ARCH->convStringWCToMB(NULL, tmp, size, errors);
   char *mbs = new char[len + 1];
   ARCH->convStringWCToMB(mbs, tmp, size, errors);
-  String text(mbs, len);
+  std::string text(mbs, len);
 
   // clean up
   delete[] mbs;
@@ -229,7 +229,7 @@ String Unicode::UTF8ToText(const String &src, bool *errors)
   return text;
 }
 
-String Unicode::UCS2ToUTF8(const String &src, bool *errors)
+std::string Unicode::UCS2ToUTF8(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
@@ -239,7 +239,7 @@ String Unicode::UCS2ToUTF8(const String &src, bool *errors)
   return doUCS2ToUTF8(reinterpret_cast<const UInt8 *>(src.data()), n, errors);
 }
 
-String Unicode::UCS4ToUTF8(const String &src, bool *errors)
+std::string Unicode::UCS4ToUTF8(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
@@ -249,7 +249,7 @@ String Unicode::UCS4ToUTF8(const String &src, bool *errors)
   return doUCS4ToUTF8(reinterpret_cast<const UInt8 *>(src.data()), n, errors);
 }
 
-String Unicode::UTF16ToUTF8(const String &src, bool *errors)
+std::string Unicode::UTF16ToUTF8(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
@@ -259,7 +259,7 @@ String Unicode::UTF16ToUTF8(const String &src, bool *errors)
   return doUTF16ToUTF8(reinterpret_cast<const UInt8 *>(src.data()), n, errors);
 }
 
-String Unicode::UTF32ToUTF8(const String &src, bool *errors)
+std::string Unicode::UTF32ToUTF8(const std::string &src, bool *errors)
 {
   // default to success
   resetError(errors);
@@ -269,7 +269,7 @@ String Unicode::UTF32ToUTF8(const String &src, bool *errors)
   return doUTF32ToUTF8(reinterpret_cast<const UInt8 *>(src.data()), n, errors);
 }
 
-String Unicode::textToUTF8(const String &src, bool *errors, IArchString::EWideCharEncoding encoding)
+std::string Unicode::textToUTF8(const std::string &src, bool *errors, IArchString::EWideCharEncoding encoding)
 {
   // default to success
   resetError(errors);
@@ -281,7 +281,7 @@ String Unicode::textToUTF8(const String &src, bool *errors, IArchString::EWideCh
   ARCH->convStringMBToWC(wcs, src.c_str(), n, errors);
 
   // convert to UTF8
-  String utf8 = wideCharToUTF8(wcs, len, errors, encoding);
+  std::string utf8 = wideCharToUTF8(wcs, len, errors, encoding);
 
   // clean up
   delete[] wcs;
@@ -289,10 +289,10 @@ String Unicode::textToUTF8(const String &src, bool *errors, IArchString::EWideCh
   return utf8;
 }
 
-wchar_t *Unicode::UTF8ToWideChar(const String &src, UInt32 &size, bool *errors)
+wchar_t *Unicode::UTF8ToWideChar(const std::string &src, UInt32 &size, bool *errors)
 {
   // convert to platform's wide character encoding
-  String tmp;
+  std::string tmp;
   switch (ARCH->getWideCharEncoding()) {
   case IArchString::kUCS2:
     tmp = UTF8ToUCS2(src, errors);
@@ -324,7 +324,8 @@ wchar_t *Unicode::UTF8ToWideChar(const String &src, UInt32 &size, bool *errors)
   return dst;
 }
 
-String Unicode::wideCharToUTF8(const wchar_t *src, UInt32 size, bool *errors, IArchString::EWideCharEncoding encoding)
+std::string
+Unicode::wideCharToUTF8(const wchar_t *src, UInt32 size, bool *errors, IArchString::EWideCharEncoding encoding)
 {
   if (encoding == IArchString::kPlatformDetermined) {
     encoding = ARCH->getWideCharEncoding();
@@ -347,14 +348,14 @@ String Unicode::wideCharToUTF8(const wchar_t *src, UInt32 size, bool *errors, IA
 
   default:
     assert(0 && "unknown wide character encoding");
-    return String();
+    return std::string();
   }
 }
 
-String Unicode::doUCS2ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
+std::string Unicode::doUCS2ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
 {
   // make some space
-  String dst;
+  std::string dst;
   dst.reserve(n);
 
   // check if first character is 0xfffe or 0xfeff
@@ -387,10 +388,10 @@ String Unicode::doUCS2ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
   return dst;
 }
 
-String Unicode::doUCS4ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
+std::string Unicode::doUCS4ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
 {
   // make some space
-  String dst;
+  std::string dst;
   dst.reserve(n);
 
   // check if first character is 0xfffe or 0xfeff
@@ -423,10 +424,10 @@ String Unicode::doUCS4ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
   return dst;
 }
 
-String Unicode::doUTF16ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
+std::string Unicode::doUTF16ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
 {
   // make some space
-  String dst;
+  std::string dst;
   dst.reserve(n);
 
   // check if first character is 0xfffe or 0xfeff
@@ -482,10 +483,10 @@ String Unicode::doUTF16ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
   return dst;
 }
 
-String Unicode::doUTF32ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
+std::string Unicode::doUTF32ToUTF8(const UInt8 *data, UInt32 n, bool *errors)
 {
   // make some space
-  String dst;
+  std::string dst;
   dst.reserve(n);
 
   // check if first character is 0xfffe or 0xfeff
@@ -672,7 +673,7 @@ UInt32 Unicode::fromUTF8(const UInt8 *&data, UInt32 &n)
   return c;
 }
 
-void Unicode::toUTF8(String &dst, UInt32 c, bool *errors)
+void Unicode::toUTF8(std::string &dst, UInt32 c, bool *errors)
 {
   UInt8 data[6];
 
diff --git a/src/lib/base/Unicode.h b/src/lib/base/Unicode.h
index bd076934a..28ab2729c 100644
--- a/src/lib/base/Unicode.h
+++ b/src/lib/base/Unicode.h
@@ -19,8 +19,8 @@
 #pragma once
 
 #include "arch/IArchString.h"
-#include "base/String.h"
 #include "common/basic_types.h"
+#include <string>
 
 //! Unicode utility functions
 /*!
@@ -38,7 +38,7 @@ public:
   Returns true iff the string contains a valid sequence of UTF-8
   encoded characters.
   */
-  static bool isUTF8(const String &);
+  static bool isUTF8(const std::string &);
 
   //! Convert from UTF-8 to UCS-2 encoding
   /*!
@@ -46,7 +46,7 @@ public:
   is set to true iff any character could not be encoded in UCS-2.
   Decoding errors do not set *errors.
   */
-  static String UTF8ToUCS2(const String &, bool *errors = NULL);
+  static std::string UTF8ToUCS2(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-8 to UCS-4 encoding
   /*!
@@ -54,7 +54,7 @@ public:
   is set to true iff any character could not be encoded in UCS-4.
   Decoding errors do not set *errors.
   */
-  static String UTF8ToUCS4(const String &, bool *errors = NULL);
+  static std::string UTF8ToUCS4(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-8 to UTF-16 encoding
   /*!
@@ -62,7 +62,7 @@ public:
   is set to true iff any character could not be encoded in UTF-16.
   Decoding errors do not set *errors.
   */
-  static String UTF8ToUTF16(const String &, bool *errors = NULL);
+  static std::string UTF8ToUTF16(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-8 to UTF-32 encoding
   /*!
@@ -70,7 +70,7 @@ public:
   is set to true iff any character could not be encoded in UTF-32.
   Decoding errors do not set *errors.
   */
-  static String UTF8ToUTF32(const String &, bool *errors = NULL);
+  static std::string UTF8ToUTF32(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-8 to the current locale encoding
   /*!
@@ -78,43 +78,44 @@ public:
   NULL then *errors is set to true iff any character could not be encoded.
   Decoding errors do not set *errors.
   */
-  static String UTF8ToText(const String &, bool *errors = NULL);
+  static std::string UTF8ToText(const std::string &, bool *errors = NULL);
 
   //! Convert from UCS-2 to UTF-8
   /*!
   Convert from UCS-2 to UTF-8.  If errors is not NULL then *errors is
   set to true iff any character could not be decoded.
   */
-  static String UCS2ToUTF8(const String &, bool *errors = NULL);
+  static std::string UCS2ToUTF8(const std::string &, bool *errors = NULL);
 
   //! Convert from UCS-4 to UTF-8
   /*!
   Convert from UCS-4 to UTF-8.  If errors is not NULL then *errors is
   set to true iff any character could not be decoded.
   */
-  static String UCS4ToUTF8(const String &, bool *errors = NULL);
+  static std::string UCS4ToUTF8(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-16 to UTF-8
   /*!
   Convert from UTF-16 to UTF-8.  If errors is not NULL then *errors is
   set to true iff any character could not be decoded.
   */
-  static String UTF16ToUTF8(const String &, bool *errors = NULL);
+  static std::string UTF16ToUTF8(const std::string &, bool *errors = NULL);
 
   //! Convert from UTF-32 to UTF-8
   /*!
   Convert from UTF-32 to UTF-8.  If errors is not NULL then *errors is
   set to true iff any character could not be decoded.
   */
-  static String UTF32ToUTF8(const String &, bool *errors = NULL);
+  static std::string UTF32ToUTF8(const std::string &, bool *errors = NULL);
 
   //! Convert from the current locale encoding to UTF-8
   /*!
   Convert from the current locale encoding to UTF-8.  If errors is not
   NULL then *errors is set to true iff any character could not be decoded.
   */
-  static String textToUTF8(
-      const String &, bool *errors = nullptr, IArchString::EWideCharEncoding encoding = IArchString::kPlatformDetermined
+  static std::string textToUTF8(
+      const std::string &, bool *errors = nullptr,
+      IArchString::EWideCharEncoding encoding = IArchString::kPlatformDetermined
   );
 
   //@}
@@ -124,24 +125,24 @@ private:
   // to the platform).  caller must delete[] the returned string.  the
   // string is *not* nul terminated;  the length (in characters) is
   // returned in size.
-  static wchar_t *UTF8ToWideChar(const String &, UInt32 &size, bool *errors);
+  static wchar_t *UTF8ToWideChar(const std::string &, UInt32 &size, bool *errors);
 
   // convert nul terminated wchar_t string (in platform's native
   // encoding) to UTF8.
-  static String wideCharToUTF8(
+  static std::string wideCharToUTF8(
       const wchar_t *, UInt32 size, bool *errors,
       IArchString::EWideCharEncoding encoding = IArchString::kPlatformDetermined
   );
 
   // internal conversion to UTF8
-  static String doUCS2ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
-  static String doUCS4ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
-  static String doUTF16ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
-  static String doUTF32ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
+  static std::string doUCS2ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
+  static std::string doUCS4ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
+  static std::string doUTF16ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
+  static std::string doUTF32ToUTF8(const UInt8 *src, UInt32 n, bool *errors);
 
   // convert characters to/from UTF8
   static UInt32 fromUTF8(const UInt8 *&src, UInt32 &size);
-  static void toUTF8(String &dst, UInt32 c, bool *errors);
+  static void toUTF8(std::string &dst, UInt32 c, bool *errors);
 
 private:
   static UInt32 s_invalid;
diff --git a/src/lib/base/XBase.cpp b/src/lib/base/XBase.cpp
index 8dd1bd12d..f7a594caa 100644
--- a/src/lib/base/XBase.cpp
+++ b/src/lib/base/XBase.cpp
@@ -32,7 +32,7 @@ XBase::XBase() : std::runtime_error("")
   // do nothing
 }
 
-XBase::XBase(const String &msg) : std::runtime_error(msg)
+XBase::XBase(const std::string &msg) : std::runtime_error(msg)
 {
   // do nothing
 }
@@ -52,13 +52,13 @@ const char *XBase::what() const _NOEXCEPT
   return m_what.c_str();
 }
 
-String XBase::format(const char * /*id*/, const char *fmt, ...) const throw()
+std::string XBase::format(const char * /*id*/, const char *fmt, ...) const throw()
 {
   // FIXME -- lookup message string using id as an index.  set
   // fmt to that string if it exists.
 
   // format
-  String result;
+  std::string result;
   va_list args;
   va_start(args, fmt);
   try {
diff --git a/src/lib/base/XBase.h b/src/lib/base/XBase.h
index 496cc1bcf..2a00c7992 100644
--- a/src/lib/base/XBase.h
+++ b/src/lib/base/XBase.h
@@ -18,8 +18,8 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdexcept.h"
+#include <string>
 
 //! Exception base class
 /*!
@@ -31,7 +31,7 @@ public:
   //! Use getWhat() as the result of what()
   XBase();
   //! Use \c msg as the result of what()
-  XBase(const String &msg);
+  XBase(const std::string &msg);
   virtual ~XBase() _NOEXCEPT;
 
   //! Reason for exception
@@ -39,7 +39,7 @@ public:
 
 protected:
   //! Get a human readable string describing the exception
-  virtual String getWhat() const throw()
+  virtual std::string getWhat() const throw()
   {
     return "";
   }
@@ -50,16 +50,16 @@ protected:
   no format can be found, then replaces positional parameters in
   the format string and returns the result.
   */
-  virtual String format(const char *id, const char *defaultFormat, ...) const throw();
+  virtual std::string format(const char *id, const char *defaultFormat, ...) const throw();
 
 private:
-  mutable String m_what;
+  mutable std::string m_what;
 };
 
 /*!
 \def XBASE_SUBCLASS
 Convenience macro to subclass from XBase (or a subclass of it),
-providing the c'tor taking a const String&.  getWhat() is not
+providing the c'tor taking a const std::string&.  getWhat() is not
 declared.
 */
 #define XBASE_SUBCLASS(name_, super_)                                                                                  \
@@ -69,7 +69,7 @@ declared.
     name_() : super_()                                                                                                 \
     {                                                                                                                  \
     }                                                                                                                  \
-    name_(const String &msg) : super_(msg)                                                                             \
+    name_(const std::string &msg) : super_(msg)                                                                        \
     {                                                                                                                  \
     }                                                                                                                  \
     virtual ~name_() _NOEXCEPT                                                                                         \
@@ -80,7 +80,7 @@ declared.
 /*!
 \def XBASE_SUBCLASS
 Convenience macro to subclass from XBase (or a subclass of it),
-providing the c'tor taking a const String&.  getWhat() must be
+providing the c'tor taking a const std::string&.  getWhat() must be
 implemented.
 */
 #define XBASE_SUBCLASS_WHAT(name_, super_)                                                                             \
@@ -90,7 +90,7 @@ implemented.
     name_() : super_()                                                                                                 \
     {                                                                                                                  \
     }                                                                                                                  \
-    name_(const String &msg) : super_(msg)                                                                             \
+    name_(const std::string &msg) : super_(msg)                                                                        \
     {                                                                                                                  \
     }                                                                                                                  \
     virtual ~name_() _NOEXCEPT                                                                                         \
@@ -98,13 +98,13 @@ implemented.
     }                                                                                                                  \
                                                                                                                        \
   protected:                                                                                                           \
-    virtual String getWhat() const throw();                                                                            \
+    virtual std::string getWhat() const throw();                                                                       \
   }
 
 /*!
 \def XBASE_SUBCLASS_FORMAT
 Convenience macro to subclass from XBase (or a subclass of it),
-providing the c'tor taking a const String&.  what() is overridden
+providing the c'tor taking a const std::string&.  what() is overridden
 to call getWhat() when first called;  getWhat() can format the
 error message and can call what() to get the message passed to the
 c'tor.
@@ -124,7 +124,7 @@ c'tor.
     name_() : super_(), m_state(kDone)                                                                                 \
     {                                                                                                                  \
     }                                                                                                                  \
-    name_(const String &msg) : super_(msg), m_state(kFirst)                                                            \
+    name_(const std::string &msg) : super_(msg), m_state(kFirst)                                                       \
     {                                                                                                                  \
     }                                                                                                                  \
     virtual ~name_() _NOEXCEPT                                                                                         \
@@ -146,7 +146,7 @@ c'tor.
     }                                                                                                                  \
                                                                                                                        \
   protected:                                                                                                           \
-    virtual String getWhat() const throw();                                                                            \
+    virtual std::string getWhat() const throw();                                                                       \
                                                                                                                        \
   private:                                                                                                             \
     mutable EState m_state;                                                                                            \
diff --git a/src/lib/base/log_outputters.cpp b/src/lib/base/log_outputters.cpp
index 081a1d4a7..2cfe0c037 100644
--- a/src/lib/base/log_outputters.cpp
+++ b/src/lib/base/log_outputters.cpp
@@ -19,6 +19,7 @@
 #include "base/log_outputters.h"
 #include "arch/Arch.h"
 #include "base/Path.h"
+#include "base/String.h"
 #include "base/TMethodJob.h"
 
 #include <fstream>
@@ -205,7 +206,7 @@ bool BufferedLogOutputter::write(ELevel, const char *message)
   while (m_buffer.size() >= m_maxBufferSize) {
     m_buffer.pop_front();
   }
-  m_buffer.push_back(String(message));
+  m_buffer.push_back(std::string(message));
   return true;
 }
 
@@ -246,7 +247,7 @@ bool FileLogOutputter::write(ELevel level, const char *message)
   m_handle.close();
 
   if (moveFile) {
-    String oldLogFilename = deskflow::string::sprintf("%s.1", m_fileName.c_str());
+    std::string oldLogFilename = deskflow::string::sprintf("%s.1", m_fileName.c_str());
     remove(oldLogFilename.c_str());
     rename(m_fileName.c_str(), oldLogFilename.c_str());
   }
diff --git a/src/lib/base/log_outputters.h b/src/lib/base/log_outputters.h
index 03393c91c..8847204b2 100644
--- a/src/lib/base/log_outputters.h
+++ b/src/lib/base/log_outputters.h
@@ -19,13 +19,13 @@
 #pragma once
 
 #include "base/ILogOutputter.h"
-#include "base/String.h"
 #include "common/basic_types.h"
 #include "common/stddeque.h"
 #include "mt/Thread.h"
 
 #include <fstream>
 #include <list>
+#include <string>
 
 //! Stop traversing log chain outputter
 /*!
@@ -137,7 +137,7 @@ This outputter records the last N log messages.
 class BufferedLogOutputter : public ILogOutputter
 {
 private:
-  using Buffer = std::deque<String>;
+  using Buffer = std::deque<std::string>;
 
 public:
   using const_iterator = Buffer::const_iterator;
diff --git a/src/lib/client/Client.cpp b/src/lib/client/Client.cpp
index 987b047d0..09895ba02 100644
--- a/src/lib/client/Client.cpp
+++ b/src/lib/client/Client.cpp
@@ -57,7 +57,7 @@ using namespace deskflow::client;
 //
 
 Client::Client(
-    IEventQueue *events, const String &name, const NetworkAddress &address, ISocketFactory *socketFactory,
+    IEventQueue *events, const std::string &name, const NetworkAddress &address, ISocketFactory *socketFactory,
     deskflow::Screen *screen, deskflow::ClientArgs const &args
 )
     : m_mock(false),
@@ -299,12 +299,12 @@ void Client::setClipboardDirty(ClipboardID, bool)
   assert(0 && "shouldn't be called");
 }
 
-void Client::keyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang)
+void Client::keyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   m_screen->keyDown(id, mask, button, lang);
 }
 
-void Client::keyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+void Client::keyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang)
 {
   m_screen->keyRepeat(id, mask, count, button, lang);
 }
@@ -378,7 +378,7 @@ void Client::setOptions(const OptionsList &options)
   m_screen->setOptions(options);
 }
 
-String Client::getName() const
+std::string Client::getName() const
 {
   return m_name;
 }
@@ -402,7 +402,7 @@ void Client::sendClipboard(ClipboardID id)
   // check time
   if (m_timeClipboard[id] == 0 || clipboard.getTime() != m_timeClipboard[id]) {
     // marshall the data
-    String data = clipboard.marshall();
+    std::string data = clipboard.marshall();
     if (data.size() >= m_maximumClipboardSize * 1024) {
       LOG(
           (CLOG_NOTE "skipping clipboard transfer because the clipboard"
@@ -757,7 +757,7 @@ void Client::writeToDropDirThread(void *)
   DropHelper::writeToDir(m_screen->getDropTarget(), m_dragFileList, m_receivedFileData);
 }
 
-void Client::dragInfoReceived(UInt32 fileNum, String data)
+void Client::dragInfoReceived(UInt32 fileNum, std::string data)
 {
   // TODO: fix duplicate function from CServer
   if (!m_args.m_enableDragDrop) {
@@ -798,7 +798,7 @@ void Client::sendFileThread(void *filename)
   m_sendFileThread.reset(nullptr);
 }
 
-void Client::sendDragInfo(UInt32 fileCount, String &info, size_t size)
+void Client::sendDragInfo(UInt32 fileCount, std::string &info, size_t size)
 {
   m_server->sendDragInfo(fileCount, info.c_str(), size);
 }
diff --git a/src/lib/client/Client.h b/src/lib/client/Client.h
index f55d8b659..799c71d6e 100644
--- a/src/lib/client/Client.h
+++ b/src/lib/client/Client.h
@@ -59,7 +59,7 @@ public:
     {
     }
     bool m_retry;
-    String m_what;
+    std::string m_what;
   };
 
 public:
@@ -69,7 +69,7 @@ public:
   to create the socket.  \p screen is    the local screen.
   */
   Client(
-      IEventQueue *events, const String &name, const NetworkAddress &address, ISocketFactory *socketFactory,
+      IEventQueue *events, const std::string &name, const NetworkAddress &address, ISocketFactory *socketFactory,
       deskflow::Screen *screen, deskflow::ClientArgs const &args
   );
   Client(Client const &) = delete;
@@ -109,13 +109,13 @@ public:
   virtual void handshakeComplete();
 
   //! Received drag information
-  void dragInfoReceived(UInt32 fileNum, String data);
+  void dragInfoReceived(UInt32 fileNum, std::string data);
 
   //! Create a new thread and use it to send file to Server
   void sendFileToServer(const char *filename);
 
   //! Send dragging file information back to server
-  void sendDragInfo(UInt32 fileCount, String &info, size_t size);
+  void sendDragInfo(UInt32 fileCount, std::string &info, size_t size);
 
   //@}
   //! @name accessors
@@ -151,7 +151,7 @@ public:
   }
 
   //! Return received file data
-  String &getReceivedFileData()
+  std::string &getReceivedFileData()
   {
     return m_receivedFileData;
   }
@@ -182,8 +182,8 @@ public:
   virtual void setClipboard(ClipboardID, const IClipboard *);
   virtual void grabClipboard(ClipboardID);
   virtual void setClipboardDirty(ClipboardID, bool);
-  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const String &);
-  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &lang);
+  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &);
+  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &lang);
   virtual void keyUp(KeyID, KeyModifierMask, KeyButton);
   virtual void mouseDown(ButtonID);
   virtual void mouseUp(ButtonID);
@@ -193,7 +193,7 @@ public:
   virtual void screensaver(bool activate);
   virtual void resetOptions();
   virtual void setOptions(const OptionsList &options);
-  virtual String getName() const;
+  virtual std::string getName() const;
 
 private:
   void sendClipboard(ClipboardID);
@@ -233,7 +233,7 @@ public:
   bool m_mock;
 
 private:
-  String m_name;
+  std::string m_name;
   NetworkAddress m_serverAddress;
   ISocketFactory *m_socketFactory;
   deskflow::Screen *m_screen;
@@ -247,12 +247,12 @@ private:
   bool m_ownClipboard[kClipboardEnd];
   bool m_sentClipboard[kClipboardEnd];
   IClipboard::Time m_timeClipboard[kClipboardEnd];
-  String m_dataClipboard[kClipboardEnd];
+  std::string m_dataClipboard[kClipboardEnd];
   IEventQueue *m_events;
   std::size_t m_expectedFileSize;
-  String m_receivedFileData;
+  std::string m_receivedFileData;
   DragFileList m_dragFileList;
-  String m_dragFileExt;
+  std::string m_dragFileExt;
   using AutoThread = std::unique_ptr<Thread>;
   AutoThread m_sendFileThread;
   AutoThread m_writeToDropDirThread;
diff --git a/src/lib/client/ServerProxy.cpp b/src/lib/client/ServerProxy.cpp
index 38d82ff12..5f65806d6 100644
--- a/src/lib/client/ServerProxy.cpp
+++ b/src/lib/client/ServerProxy.cpp
@@ -250,7 +250,7 @@ ServerProxy::EResult ServerProxy::parseMessage(const UInt8 *code)
   }
 
   else if (memcmp(code, kMsgDKeyDownLang, 4) == 0) {
-    String lang;
+    std::string lang;
     UInt16 id = 0;
     UInt16 mask = 0;
     UInt16 button = 0;
@@ -382,7 +382,7 @@ bool ServerProxy::onGrabClipboard(ClipboardID id)
 
 void ServerProxy::onClipboardChanged(ClipboardID id, const IClipboard *clipboard)
 {
-  String data = IClipboard::marshall(clipboard);
+  std::string data = IClipboard::marshall(clipboard);
   LOG((CLOG_DEBUG "sending clipboard %d seqnum=%d", id, m_seqNum));
 
   StreamChunker::sendClipboard(data, data.size(), id, m_seqNum, m_events, this);
@@ -547,7 +547,7 @@ void ServerProxy::leave()
 void ServerProxy::setClipboard()
 {
   // parse
-  static String dataCached;
+  static std::string dataCached;
   ClipboardID id;
   UInt32 seq;
 
@@ -585,7 +585,7 @@ void ServerProxy::grabClipboard()
   m_client->grabClipboard(id);
 }
 
-void ServerProxy::keyDown(UInt16 id, UInt16 mask, UInt16 button, const String &lang)
+void ServerProxy::keyDown(UInt16 id, UInt16 mask, UInt16 button, const std::string &lang)
 {
   // get mouse up to date
   flushCompressedMouse();
@@ -608,7 +608,7 @@ void ServerProxy::keyRepeat()
 
   // parse
   UInt16 id, mask, count, button;
-  String lang;
+  std::string lang;
   ProtocolUtil::readf(m_stream, kMsgDKeyRepeat + 4, &id, &mask, &count, &button, &lang);
   LOG(
       (CLOG_DEBUG1 "recv key repeat id=0x%08x, mask=0x%04x, count=%d, "
@@ -836,7 +836,7 @@ void ServerProxy::fileChunkReceived()
     m_events->addEvent(Event(m_events->forFile().fileRecieveCompleted(), m_client));
   } else if (result == kStart) {
     if (m_client->getDragFileList().size() > 0) {
-      String filename = m_client->getDragFileList().at(0).getFilename();
+      std::string filename = m_client->getDragFileList().at(0).getFilename();
       LOG((CLOG_DEBUG "start receiving %s", filename.c_str()));
     }
   }
@@ -846,7 +846,7 @@ void ServerProxy::dragInfoReceived()
 {
   // parse
   UInt32 fileNum = 0;
-  String content;
+  std::string content;
   ProtocolUtil::readf(m_stream, kMsgDDragInfo + 4, &fileNum, &content);
 
   m_client->dragInfoReceived(fileNum, content);
@@ -864,13 +864,13 @@ void ServerProxy::fileChunkSending(UInt8 mark, char *data, size_t dataSize)
 
 void ServerProxy::sendDragInfo(UInt32 fileCount, const char *info, size_t size)
 {
-  String data(info, size);
+  std::string data(info, size);
   ProtocolUtil::writef(m_stream, kMsgDDragInfo, fileCount, &data);
 }
 
 void ServerProxy::secureInputNotification()
 {
-  String app;
+  std::string app;
   ProtocolUtil::readf(m_stream, kMsgDSecureInputNotification + 4, &app);
 
   // display this notification on the client
@@ -891,12 +891,12 @@ void ServerProxy::secureInputNotification()
 
 void ServerProxy::setServerLanguages()
 {
-  String serverLanguages;
+  std::string serverLanguages;
   ProtocolUtil::readf(m_stream, kMsgDLanguageSynchronisation + 4, &serverLanguages);
   m_languageManager.setRemoteLanguages(serverLanguages);
 }
 
-void ServerProxy::setActiveServerLanguage(const String &language)
+void ServerProxy::setActiveServerLanguage(const std::string &language)
 {
   if (!language.empty() && std::strlen(language.c_str()) > 0) {
     if (m_serverLanguage != language) {
diff --git a/src/lib/client/ServerProxy.h b/src/lib/client/ServerProxy.h
index 743c3393f..1275cbb95 100644
--- a/src/lib/client/ServerProxy.h
+++ b/src/lib/client/ServerProxy.h
@@ -20,7 +20,6 @@
 
 #include "base/Event.h"
 #include "base/Stopwatch.h"
-#include "base/String.h"
 #include "deskflow/clipboard_types.h"
 #include "deskflow/key_types.h"
 #include "deskflow/languages/LanguageManager.h"
@@ -108,7 +107,7 @@ private:
   void leave();
   void setClipboard();
   void grabClipboard();
-  void keyDown(UInt16 id, UInt16 mask, UInt16 button, const String &lang);
+  void keyDown(UInt16 id, UInt16 mask, UInt16 button, const std::string &lang);
   void keyRepeat();
   void keyUp();
   void mouseDown();
@@ -126,7 +125,7 @@ private:
   void handleClipboardSendingEvent(const Event &, void *);
   void secureInputNotification();
   void setServerLanguages();
-  void setActiveServerLanguage(const String &language);
+  void setActiveServerLanguage(const std::string &language);
   void checkMissedLanguages() const;
 
 private:
@@ -151,7 +150,7 @@ private:
 
   MessageParser m_parser;
   IEventQueue *m_events;
-  String m_serverLanguage = "";
+  std::string m_serverLanguage = "";
   bool m_isUserNotifiedAboutLanguageSyncError = false;
   deskflow::languages::LanguageManager m_languageManager;
 };
diff --git a/src/lib/deskflow/App.cpp b/src/lib/deskflow/App.cpp
index eef004368..47622b21c 100644
--- a/src/lib/deskflow/App.cpp
+++ b/src/lib/deskflow/App.cpp
@@ -319,7 +319,7 @@ void MinimalApp::loadConfig()
 {
 }
 
-bool MinimalApp::loadConfig(const String &pathname)
+bool MinimalApp::loadConfig(const std::string &pathname)
 {
   return false;
 }
diff --git a/src/lib/deskflow/App.h b/src/lib/deskflow/App.h
index d58016af4..c77298def 100644
--- a/src/lib/deskflow/App.h
+++ b/src/lib/deskflow/App.h
@@ -20,7 +20,6 @@
 
 #include "base/EventQueue.h"
 #include "base/Log.h"
-#include "base/String.h"
 #include "common/common.h"
 #include "deskflow/IApp.h"
 #include "ipc/IpcClient.h"
@@ -67,7 +66,7 @@ public:
   virtual void help() = 0;
   virtual void parseArgs(int argc, const char *const *argv) = 0;
   virtual void loadConfig() = 0;
-  virtual bool loadConfig(const String &pathname) = 0;
+  virtual bool loadConfig(const std::string &pathname) = 0;
   virtual const char *daemonInfo() const = 0;
   virtual std::string configSection() const = 0;
 
@@ -165,7 +164,7 @@ public:
   virtual int foregroundStartup(int argc, char **argv) override;
   virtual deskflow::Screen *createScreen() override;
   virtual void loadConfig() override;
-  virtual bool loadConfig(const String &pathname) override;
+  virtual bool loadConfig(const std::string &pathname) override;
   virtual const char *daemonInfo() const override;
   virtual const char *daemonName() const override;
   virtual void parseArgs(int argc, const char *const *argv) override;
diff --git a/src/lib/deskflow/ArgParser.cpp b/src/lib/deskflow/ArgParser.cpp
index 9e677e52c..5f67d9d24 100644
--- a/src/lib/deskflow/ArgParser.cpp
+++ b/src/lib/deskflow/ArgParser.cpp
@@ -18,7 +18,6 @@
 #include "deskflow/ArgParser.h"
 
 #include "base/Log.h"
-#include "base/String.h"
 #include "deskflow/App.h"
 #include "deskflow/ArgsBase.h"
 #include "deskflow/ClientArgs.h"
@@ -284,7 +283,7 @@ bool ArgParser::isArg(
   return false;
 }
 
-void ArgParser::splitCommandString(String &command, std::vector<String> &argv)
+void ArgParser::splitCommandString(std::string &command, std::vector<std::string> &argv)
 {
   if (command.empty()) {
     return;
@@ -297,7 +296,7 @@ void ArgParser::splitCommandString(String &command, std::vector<String> &argv)
   size_t startPos = 0;
   size_t space = command.find(" ", startPos);
 
-  while (space != String::npos) {
+  while (space != std::string::npos) {
     bool ignoreThisSpace = false;
 
     // check if the space is between two double quotes
@@ -308,7 +307,7 @@ void ArgParser::splitCommandString(String &command, std::vector<String> &argv)
     }
 
     if (!ignoreThisSpace) {
-      String subString = command.substr(startPos, space - startPos);
+      std::string subString = command.substr(startPos, space - startPos);
 
       removeDoubleQuotes(subString);
       argv.push_back(subString);
@@ -323,21 +322,21 @@ void ArgParser::splitCommandString(String &command, std::vector<String> &argv)
     }
   }
 
-  String subString = command.substr(startPos, command.size());
+  std::string subString = command.substr(startPos, command.size());
   removeDoubleQuotes(subString);
   argv.push_back(subString);
 }
 
-bool ArgParser::searchDoubleQuotes(String &command, size_t &left, size_t &right, size_t startPos)
+bool ArgParser::searchDoubleQuotes(std::string &command, size_t &left, size_t &right, size_t startPos)
 {
   bool result = false;
-  left = String::npos;
-  right = String::npos;
+  left = std::string::npos;
+  right = std::string::npos;
 
   left = command.find("\"", startPos);
-  if (left != String::npos) {
+  if (left != std::string::npos) {
     right = command.find("\"", left + 1);
-    if (right != String::npos) {
+    if (right != std::string::npos) {
       result = true;
     }
   }
@@ -350,7 +349,7 @@ bool ArgParser::searchDoubleQuotes(String &command, size_t &left, size_t &right,
   return result;
 }
 
-void ArgParser::removeDoubleQuotes(String &arg)
+void ArgParser::removeDoubleQuotes(std::string &arg)
 {
   // if string is surrounded by double quotes, remove them
   if (arg[0] == '\"' && arg[arg.size() - 1] == '\"') {
@@ -358,7 +357,7 @@ void ArgParser::removeDoubleQuotes(String &arg)
   }
 }
 
-const char **ArgParser::getArgv(std::vector<String> &argsArray)
+const char **ArgParser::getArgv(std::vector<std::string> &argsArray)
 {
   size_t argc = argsArray.size();
 
@@ -375,18 +374,19 @@ const char **ArgParser::getArgv(std::vector<String> &argsArray)
   return argv;
 }
 
-String ArgParser::assembleCommand(std::vector<String> &argsArray, String ignoreArg, int parametersRequired)
+std::string
+ArgParser::assembleCommand(std::vector<std::string> &argsArray, std::string ignoreArg, int parametersRequired)
 {
-  String result;
+  std::string result;
 
-  for (std::vector<String>::iterator it = argsArray.begin(); it != argsArray.end(); ++it) {
+  for (std::vector<std::string>::iterator it = argsArray.begin(); it != argsArray.end(); ++it) {
     if (it->compare(ignoreArg) == 0) {
       it = it + parametersRequired;
       continue;
     }
 
     // if there is a space in this arg, use double quotes surround it
-    if ((*it).find(" ") != String::npos) {
+    if ((*it).find(" ") != std::string::npos) {
       (*it).insert(0, "\"");
       (*it).push_back('\"');
     }
diff --git a/src/lib/deskflow/ArgParser.h b/src/lib/deskflow/ArgParser.h
index d0c2abd04..607e6454b 100644
--- a/src/lib/deskflow/ArgParser.h
+++ b/src/lib/deskflow/ArgParser.h
@@ -17,9 +17,10 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdvector.h"
 
+#include <string>
+
 namespace deskflow {
 class ArgsBase;
 class ServerArgs;
@@ -47,11 +48,12 @@ public:
   static bool isArg(
       int argi, int argc, const char *const *argv, const char *name1, const char *name2, int minRequiredParameters = 0
   );
-  static void splitCommandString(String &command, std::vector<String> &argv);
-  static bool searchDoubleQuotes(String &command, size_t &left, size_t &right, size_t startPos = 0);
-  static void removeDoubleQuotes(String &arg);
-  static const char **getArgv(std::vector<String> &argsArray);
-  static String assembleCommand(std::vector<String> &argsArray, String ignoreArg = "", int parametersRequired = 0);
+  static void splitCommandString(std::string &command, std::vector<std::string> &argv);
+  static bool searchDoubleQuotes(std::string &command, size_t &left, size_t &right, size_t startPos = 0);
+  static void removeDoubleQuotes(std::string &arg);
+  static const char **getArgv(std::vector<std::string> &argsArray);
+  static std::string
+  assembleCommand(std::vector<std::string> &argsArray, std::string ignoreArg = "", int parametersRequired = 0);
 
   static deskflow::ArgsBase &argsBase()
   {
diff --git a/src/lib/deskflow/ArgsBase.h b/src/lib/deskflow/ArgsBase.h
index 4d2911d8b..868f891d0 100644
--- a/src/lib/deskflow/ArgsBase.h
+++ b/src/lib/deskflow/ArgsBase.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "base/String.h"
+#include <string>
 
 namespace deskflow {
 
@@ -65,7 +65,7 @@ public:
   const char *m_display = nullptr;
 
   /// @brief The name of the current computer
-  String m_name;
+  std::string m_name;
 
   /// @brief Should the app add a tray icon
   bool m_disableTray = false;
@@ -83,19 +83,19 @@ public:
   bool m_shouldExitFail = false;
 
   /// @brief Bind to this address
-  String m_deskflowAddress;
+  std::string m_deskflowAddress;
 
   /// @brief Should the connections be TLS encrypted
   bool m_enableCrypto = false;
 
   /// @brief The dir to load settings from
-  String m_profileDirectory;
+  std::string m_profileDirectory;
 
   /// @brief The dir to load plugins from
-  String m_pluginDirectory;
+  std::string m_pluginDirectory;
 
   /// @brief Contains the location of the TLS certificate file
-  String m_tlsCertFile;
+  std::string m_tlsCertFile;
 
   /// @brief Stop this computer from sleeping
   bool m_preventSleep = false;
diff --git a/src/lib/deskflow/ClientApp.cpp b/src/lib/deskflow/ClientApp.cpp
index 87f15b9d1..b0d3b202c 100644
--- a/src/lib/deskflow/ClientApp.cpp
+++ b/src/lib/deskflow/ClientApp.cpp
@@ -23,7 +23,6 @@
 #include "base/Event.h"
 #include "base/IEventQueue.h"
 #include "base/Log.h"
-#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "client/Client.h"
 #include "common/constants.h"
@@ -229,7 +228,7 @@ void ClientApp::updateStatus()
   updateStatus("");
 }
 
-void ClientApp::updateStatus(const String &msg)
+void ClientApp::updateStatus(const std::string &msg)
 {
   if (m_taskBarReceiver) {
     m_taskBarReceiver->updateStatus(m_client, msg);
@@ -321,7 +320,7 @@ void ClientApp::handleClientFailed(const Event &e, void *)
   if ((++m_lastServerAddressIndex) < m_client->getLastResolvedAddressesCount()) {
     std::unique_ptr<Client::FailInfo> info(static_cast<Client::FailInfo *>(e.getData()));
 
-    updateStatus(String("Failed to connect to server: ") + info->m_what + " Trying next address...");
+    updateStatus(std::string("Failed to connect to server: ") + info->m_what + " Trying next address...");
     LOG((CLOG_NOTE "failed to connect to server=%s, trying next address", info->m_what.c_str()));
     if (!m_suspended) {
       scheduleClientRestart(nextRestartTimeout());
@@ -336,7 +335,7 @@ void ClientApp::handleClientRefused(const Event &e, void *)
 {
   std::unique_ptr<Client::FailInfo> info(static_cast<Client::FailInfo *>(e.getData()));
 
-  updateStatus(String("Failed to connect to server: ") + info->m_what);
+  updateStatus(std::string("Failed to connect to server: ") + info->m_what);
   if (!args().m_restartable || !info->m_retry) {
     LOG((CLOG_ERR "failed to connect to server: %s", info->m_what.c_str()));
     m_events->addEvent(Event(Event::kQuit));
@@ -359,7 +358,7 @@ void ClientApp::handleClientDisconnected(const Event &, void *)
   updateStatus();
 }
 
-Client *ClientApp::openClient(const String &name, const NetworkAddress &address, deskflow::Screen *screen)
+Client *ClientApp::openClient(const std::string &name, const NetworkAddress &address, deskflow::Screen *screen)
 {
   Client *client = new Client(m_events, name, address, getSocketFactory(), screen, args());
 
@@ -432,7 +431,7 @@ bool ClientApp::startClient()
   } catch (XScreenUnavailable &e) {
     LOG((CLOG_WARN "secondary screen unavailable: %s", e.what()));
     closeClientScreen(clientScreen);
-    updateStatus(String("secondary screen unavailable: ") + e.what());
+    updateStatus(std::string("secondary screen unavailable: ") + e.what());
     retryTime = e.getRetryTime();
   } catch (XScreenOpenFailure &e) {
     LOG((CLOG_CRIT "failed to start client: %s", e.what()));
diff --git a/src/lib/deskflow/ClientApp.h b/src/lib/deskflow/ClientApp.h
index 2d9cb0e48..1f5a36a30 100644
--- a/src/lib/deskflow/ClientApp.h
+++ b/src/lib/deskflow/ClientApp.h
@@ -50,7 +50,7 @@ public:
   void loadConfig() override
   {
   }
-  bool loadConfig(const String &pathname) override
+  bool loadConfig(const std::string &pathname) override
   {
     return false;
   }
@@ -75,7 +75,7 @@ public:
   //
 
   void updateStatus();
-  void updateStatus(const String &msg);
+  void updateStatus(const std::string &msg);
   void resetRestartTimeout();
   double nextRestartTimeout();
   void handleScreenError(const Event &, void *);
@@ -87,7 +87,7 @@ public:
   void handleClientFailed(const Event &e, void *);
   void handleClientRefused(const Event &e, void *);
   void handleClientDisconnected(const Event &, void *);
-  Client *openClient(const String &name, const NetworkAddress &address, deskflow::Screen *screen);
+  Client *openClient(const std::string &name, const NetworkAddress &address, deskflow::Screen *screen);
   void closeClient(Client *client);
   bool startClient();
   void stopClient();
diff --git a/src/lib/deskflow/ClientTaskBarReceiver.cpp b/src/lib/deskflow/ClientTaskBarReceiver.cpp
index 83a8346be..9ea599821 100644
--- a/src/lib/deskflow/ClientTaskBarReceiver.cpp
+++ b/src/lib/deskflow/ClientTaskBarReceiver.cpp
@@ -38,7 +38,7 @@ ClientTaskBarReceiver::~ClientTaskBarReceiver()
   // do nothing
 }
 
-void ClientTaskBarReceiver::updateStatus(Client *client, const String &errorMsg)
+void ClientTaskBarReceiver::updateStatus(Client *client, const std::string &errorMsg)
 {
   {
     // update our status
@@ -74,7 +74,7 @@ ClientTaskBarReceiver::EState ClientTaskBarReceiver::getStatus() const
   return m_state;
 }
 
-const String &ClientTaskBarReceiver::getErrorMessage() const
+const std::string &ClientTaskBarReceiver::getErrorMessage() const
 {
   return m_errorMessage;
 }
diff --git a/src/lib/deskflow/ClientTaskBarReceiver.h b/src/lib/deskflow/ClientTaskBarReceiver.h
index e09024540..baa84fe7c 100644
--- a/src/lib/deskflow/ClientTaskBarReceiver.h
+++ b/src/lib/deskflow/ClientTaskBarReceiver.h
@@ -19,7 +19,6 @@
 #pragma once
 
 #include "arch/IArchTaskBarReceiver.h"
-#include "base/String.h"
 #include "base/log_outputters.h"
 #include "client/Client.h"
 
@@ -39,9 +38,9 @@ public:
   /*!
   Determine the status and query required information from the client.
   */
-  void updateStatus(Client *, const String &errorMsg);
+  void updateStatus(Client *, const std::string &errorMsg);
 
-  void updateStatus(INode *n, const String &errorMsg)
+  void updateStatus(INode *n, const std::string &errorMsg)
   {
     updateStatus((Client *)n, errorMsg);
   }
@@ -75,7 +74,7 @@ protected:
   EState getStatus() const;
 
   //! Get error message
-  const String &getErrorMessage() const;
+  const std::string &getErrorMessage() const;
 
   //! Quit app
   /*!
@@ -91,8 +90,8 @@ protected:
 
 private:
   EState m_state;
-  String m_errorMessage;
-  String m_server;
+  std::string m_errorMessage;
+  std::string m_server;
   IEventQueue *m_events;
 };
 
diff --git a/src/lib/deskflow/Clipboard.cpp b/src/lib/deskflow/Clipboard.cpp
index 859764997..a3326be89 100644
--- a/src/lib/deskflow/Clipboard.cpp
+++ b/src/lib/deskflow/Clipboard.cpp
@@ -53,7 +53,7 @@ bool Clipboard::empty()
   return true;
 }
 
-void Clipboard::add(EFormat format, const String &data)
+void Clipboard::add(EFormat format, const std::string &data)
 {
   assert(m_open);
   assert(m_owner);
@@ -90,18 +90,18 @@ bool Clipboard::has(EFormat format) const
   return m_added[format];
 }
 
-String Clipboard::get(EFormat format) const
+std::string Clipboard::get(EFormat format) const
 {
   assert(m_open);
   return m_data[format];
 }
 
-void Clipboard::unmarshall(const String &data, Time time)
+void Clipboard::unmarshall(const std::string &data, Time time)
 {
   IClipboard::unmarshall(this, data, time);
 }
 
-String Clipboard::marshall() const
+std::string Clipboard::marshall() const
 {
   return IClipboard::marshall(this);
 }
diff --git a/src/lib/deskflow/Clipboard.h b/src/lib/deskflow/Clipboard.h
index 8d9436fb2..1a5791a12 100644
--- a/src/lib/deskflow/Clipboard.h
+++ b/src/lib/deskflow/Clipboard.h
@@ -38,7 +38,7 @@ public:
   Extract marshalled clipboard data and store it in this clipboard.
   Sets the clipboard time to \c time.
   */
-  void unmarshall(const String &data, Time time);
+  void unmarshall(const std::string &data, Time time);
 
   //@}
   //! @name accessors
@@ -49,18 +49,18 @@ public:
   Merge this clipboard's data into a single buffer that can be later
   unmarshalled to restore the clipboard and return the buffer.
   */
-  String marshall() const;
+  std::string marshall() const;
 
   //@}
 
   // IClipboard overrides
   virtual bool empty();
-  virtual void add(EFormat, const String &data);
+  virtual void add(EFormat, const std::string &data);
   virtual bool open(Time) const;
   virtual void close() const;
   virtual Time getTime() const;
   virtual bool has(EFormat) const;
-  virtual String get(EFormat) const;
+  virtual std::string get(EFormat) const;
 
 private:
   mutable bool m_open;
@@ -68,5 +68,5 @@ private:
   bool m_owner;
   Time m_timeOwned;
   bool m_added[kNumFormats];
-  String m_data[kNumFormats];
+  std::string m_data[kNumFormats];
 };
diff --git a/src/lib/deskflow/ClipboardChunk.cpp b/src/lib/deskflow/ClipboardChunk.cpp
index b5962638e..b12732ae8 100644
--- a/src/lib/deskflow/ClipboardChunk.cpp
+++ b/src/lib/deskflow/ClipboardChunk.cpp
@@ -18,6 +18,7 @@
 #include "deskflow/ClipboardChunk.h"
 
 #include "base/Log.h"
+#include "base/String.h"
 #include "deskflow/ProtocolUtil.h"
 #include "deskflow/protocol_types.h"
 #include "io/IStream.h"
@@ -30,7 +31,7 @@ ClipboardChunk::ClipboardChunk(size_t size) : Chunk(size)
   m_dataSize = size - CLIPBOARD_CHUNK_META_SIZE;
 }
 
-ClipboardChunk *ClipboardChunk::start(ClipboardID id, UInt32 sequence, const String &size)
+ClipboardChunk *ClipboardChunk::start(ClipboardID id, UInt32 sequence, const std::string &size)
 {
   size_t sizeLength = size.size();
   ClipboardChunk *start = new ClipboardChunk(sizeLength + CLIPBOARD_CHUNK_META_SIZE);
@@ -45,7 +46,7 @@ ClipboardChunk *ClipboardChunk::start(ClipboardID id, UInt32 sequence, const Str
   return start;
 }
 
-ClipboardChunk *ClipboardChunk::data(ClipboardID id, UInt32 sequence, const String &data)
+ClipboardChunk *ClipboardChunk::data(ClipboardID id, UInt32 sequence, const std::string &data)
 {
   size_t dataSize = data.size();
   ClipboardChunk *chunk = new ClipboardChunk(dataSize + CLIPBOARD_CHUNK_META_SIZE);
@@ -73,10 +74,10 @@ ClipboardChunk *ClipboardChunk::end(ClipboardID id, UInt32 sequence)
   return end;
 }
 
-int ClipboardChunk::assemble(deskflow::IStream *stream, String &dataCached, ClipboardID &id, UInt32 &sequence)
+int ClipboardChunk::assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, UInt32 &sequence)
 {
   UInt8 mark;
-  String data;
+  std::string data;
 
   if (!ProtocolUtil::readf(stream, kMsgDClipboard + 4, &id, &sequence, &mark, &data)) {
     return kError;
@@ -116,7 +117,7 @@ void ClipboardChunk::send(deskflow::IStream *stream, void *data)
   UInt32 sequence;
   std::memcpy(&sequence, &chunk[1], 4);
   UInt8 mark = chunk[5];
-  String dataChunk(&chunk[6], clipboardData->m_dataSize);
+  std::string dataChunk(&chunk[6], clipboardData->m_dataSize);
 
   switch (mark) {
   case kDataStart:
diff --git a/src/lib/deskflow/ClipboardChunk.h b/src/lib/deskflow/ClipboardChunk.h
index 61594cbef..a55e50f6d 100644
--- a/src/lib/deskflow/ClipboardChunk.h
+++ b/src/lib/deskflow/ClipboardChunk.h
@@ -17,11 +17,12 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/basic_types.h"
 #include "deskflow/Chunk.h"
 #include "deskflow/clipboard_types.h"
 
+#include <string>
+
 #define CLIPBOARD_CHUNK_META_SIZE 7
 
 namespace deskflow {
@@ -33,11 +34,11 @@ class ClipboardChunk : public Chunk
 public:
   ClipboardChunk(size_t size);
 
-  static ClipboardChunk *start(ClipboardID id, UInt32 sequence, const String &size);
-  static ClipboardChunk *data(ClipboardID id, UInt32 sequence, const String &data);
+  static ClipboardChunk *start(ClipboardID id, UInt32 sequence, const std::string &size);
+  static ClipboardChunk *data(ClipboardID id, UInt32 sequence, const std::string &data);
   static ClipboardChunk *end(ClipboardID id, UInt32 sequence);
 
-  static int assemble(deskflow::IStream *stream, String &dataCached, ClipboardID &id, UInt32 &sequence);
+  static int assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, UInt32 &sequence);
 
   static void send(deskflow::IStream *stream, void *data);
 
diff --git a/src/lib/deskflow/DaemonApp.cpp b/src/lib/deskflow/DaemonApp.cpp
index 9444ad993..cf3949f33 100644
--- a/src/lib/deskflow/DaemonApp.cpp
+++ b/src/lib/deskflow/DaemonApp.cpp
@@ -73,13 +73,13 @@ void updateSetting(const IpcMessage &message)
   }
 }
 
-bool isServerCommandLine(const std::vector<String> &cmd)
+bool isServerCommandLine(const std::vector<std::string> &cmd)
 {
   auto isServer = false;
 
   if (cmd.size() > 1) {
-    isServer = (cmd[0].find("deskflow-server") != String::npos) ||
-               (cmd[0].find("deskflow-core") != String::npos && cmd[1] == "server");
+    isServer = (cmd[0].find("deskflow-server") != std::string::npos) ||
+               (cmd[0].find("deskflow-core") != std::string::npos && cmd[1] == "server");
   }
 
   return isServer;
@@ -188,8 +188,8 @@ int DaemonApp::run(int argc, char **argv)
 
     return kExitSuccess;
   } catch (XArch &e) {
-    String message = e.what();
-    if (uninstall && (message.find("The service has not been started") != String::npos)) {
+    std::string message = e.what();
+    if (uninstall && (message.find("The service has not been started") != std::string::npos)) {
       // TODO: if we're keeping this use error code instead (what is it?!).
       // HACK: this message happens intermittently, not sure where from but
       // it's quite misleading for the user. they thing something has gone
@@ -246,7 +246,7 @@ void DaemonApp::mainLoop(bool logToFile, bool foreground)
     // install the platform event queue to handle service stop events.
     m_events->adoptBuffer(new MSWindowsEventQueueBuffer(m_events.get()));
 
-    String command = ARCH->setting("Command");
+    std::string command = ARCH->setting("Command");
     bool elevate = ARCH->setting("Elevate") == "1";
     if (command != "") {
       LOG((CLOG_INFO "using last known command: %s", command.c_str()));
@@ -301,7 +301,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
   switch (m->type()) {
   case IpcMessageType::Command: {
     IpcCommandMessage *cm = static_cast<IpcCommandMessage *>(m);
-    String command = cm->command();
+    std::string command = cm->command();
 
     // if empty quotes, clear.
     if (command == "\"\"") {
@@ -312,7 +312,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
       LOG((CLOG_DEBUG "daemon got new core command"));
       LOG((CLOG_DEBUG2 "new command, elevate=%d command=%s", cm->elevate(), command.c_str()));
 
-      std::vector<String> argsArray;
+      std::vector<std::string> argsArray;
       ArgParser::splitCommandString(command, argsArray);
       ArgParser argParser(NULL);
       const char **argv = argParser.getArgv(argsArray);
@@ -327,7 +327,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
       }
 
       delete[] argv;
-      String logLevel(ArgParser::argsBase().m_logFilter);
+      std::string logLevel(ArgParser::argsBase().m_logFilter);
       if (!logLevel.empty()) {
         try {
           // change log level based on that in the command string
@@ -348,7 +348,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
       ARCH->setting("Command", command);
 
       // TODO: it would be nice to store bools/ints...
-      ARCH->setting("Elevate", String(cm->elevate() ? "1" : "0"));
+      ARCH->setting("Elevate", std::string(cm->elevate() ? "1" : "0"));
     } catch (XArch &e) {
       LOG((CLOG_ERR "failed to save settings, %s", e.what()));
     }
@@ -364,7 +364,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
 
   case IpcMessageType::Hello: {
     IpcHelloMessage *hm = static_cast<IpcHelloMessage *>(m);
-    String type;
+    std::string type;
     switch (hm->clientType()) {
     case IpcClientType::GUI:
       type = "gui";
@@ -387,7 +387,7 @@ void DaemonApp::handleIpcMessage(const Event &e, void *)
     }
 
 #if SYSAPI_WIN32
-    String watchdogStatus = m_watchdog->isProcessActive() ? "active" : "idle";
+    std::string watchdogStatus = m_watchdog->isProcessActive() ? "active" : "idle";
     LOG((CLOG_INFO "service status: %s", watchdogStatus.c_str()));
 #endif
 
diff --git a/src/lib/deskflow/DragInformation.cpp b/src/lib/deskflow/DragInformation.cpp
index 98b169a01..6227d708c 100644
--- a/src/lib/deskflow/DragInformation.cpp
+++ b/src/lib/deskflow/DragInformation.cpp
@@ -28,14 +28,14 @@ DragInformation::DragInformation() : m_filename(), m_filesize(0)
 {
 }
 
-void DragInformation::parseDragInfo(DragFileList &dragFileList, UInt32 fileNum, String data)
+void DragInformation::parseDragInfo(DragFileList &dragFileList, UInt32 fileNum, std::string data)
 {
   size_t startPos = 0;
   size_t findResult1 = 0;
   size_t findResult2 = 0;
   dragFileList.clear();
-  String slash("\\");
-  if (data.find("/", startPos) != string::npos) {
+  std::string slash("\\");
+  if (data.find("/", startPos) != std::string::npos) {
     slash = "/";
   }
 
@@ -51,7 +51,7 @@ void DragInformation::parseDragInfo(DragFileList &dragFileList, UInt32 fileNum,
 
     // set filename
     if (findResult1 - findResult2 > 1) {
-      String filename = data.substr(findResult2 + 1, findResult1 - findResult2 - 1);
+      std::string filename = data.substr(findResult2 + 1, findResult1 - findResult2 - 1);
       DragInformation di;
       di.setFilename(filename);
       dragFileList.push_back(di);
@@ -61,7 +61,7 @@ void DragInformation::parseDragInfo(DragFileList &dragFileList, UInt32 fileNum,
     // set filesize
     findResult2 = data.find(',', startPos);
     if (findResult2 - findResult1 > 1) {
-      String filesize = data.substr(findResult1 + 1, findResult2 - findResult1 - 1);
+      std::string filesize = data.substr(findResult1 + 1, findResult2 - findResult1 - 1);
       size_t size = stringToNum(filesize);
       dragFileList.at(index).setFilesize(size);
     }
@@ -77,31 +77,31 @@ void DragInformation::parseDragInfo(DragFileList &dragFileList, UInt32 fileNum,
   }
 }
 
-String DragInformation::getDragFileExtension(String filename)
+std::string DragInformation::getDragFileExtension(std::string filename)
 {
-  size_t findResult = string::npos;
+  size_t findResult = std::string::npos;
   findResult = filename.find_last_of(".", filename.size());
-  if (findResult != string::npos) {
+  if (findResult != std::string::npos) {
     return filename.substr(findResult + 1, filename.size() - findResult - 1);
   } else {
     return "";
   }
 }
 
-int DragInformation::setupDragInfo(DragFileList &fileList, String &output)
+int DragInformation::setupDragInfo(DragFileList &fileList, std::string &output)
 {
   int size = static_cast<int>(fileList.size());
   for (int i = 0; i < size; ++i) {
     output.append(fileList.at(i).getFilename());
     output.append(",");
-    String filesize = getFileSize(fileList.at(i).getFilename());
+    std::string filesize = getFileSize(fileList.at(i).getFilename());
     output.append(filesize);
     output.append(",");
   }
   return size;
 }
 
-bool DragInformation::isFileValid(String filename)
+bool DragInformation::isFileValid(std::string filename)
 {
   bool result = false;
   std::fstream file(filename.c_str(), ios::in | ios::binary);
@@ -115,7 +115,7 @@ bool DragInformation::isFileValid(String filename)
   return result;
 }
 
-size_t DragInformation::stringToNum(String &str)
+size_t DragInformation::stringToNum(std::string &str)
 {
   istringstream iss(str.c_str());
   size_t size;
@@ -123,7 +123,7 @@ size_t DragInformation::stringToNum(String &str)
   return size;
 }
 
-String DragInformation::getFileSize(String &filename)
+std::string DragInformation::getFileSize(std::string &filename)
 {
   std::fstream file(filename.c_str(), ios::in | ios::binary);
 
diff --git a/src/lib/deskflow/DragInformation.h b/src/lib/deskflow/DragInformation.h
index 2121990be..da33017d1 100644
--- a/src/lib/deskflow/DragInformation.h
+++ b/src/lib/deskflow/DragInformation.h
@@ -18,9 +18,10 @@
 #pragma once
 
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "common/stdvector.h"
 
+#include <string>
+
 class DragInformation;
 using DragFileList = std::vector<DragInformation>;
 
@@ -32,11 +33,11 @@ public:
   {
   }
 
-  String &getFilename()
+  std::string &getFilename()
   {
     return m_filename;
   }
-  void setFilename(String &name)
+  void setFilename(std::string &name)
   {
     m_filename = name;
   }
@@ -49,20 +50,20 @@ public:
     m_filesize = size;
   }
 
-  static void parseDragInfo(DragFileList &dragFileList, UInt32 fileNum, String data);
-  static String getDragFileExtension(String filename);
+  static void parseDragInfo(DragFileList &dragFileList, UInt32 fileNum, std::string data);
+  static std::string getDragFileExtension(std::string filename);
   // helper function to setup drag info
   // example: filename1,filesize1,filename2,filesize2,
   // return file count
-  static int setupDragInfo(DragFileList &fileList, String &output);
+  static int setupDragInfo(DragFileList &fileList, std::string &output);
 
-  static bool isFileValid(String filename);
+  static bool isFileValid(std::string filename);
 
 private:
-  static size_t stringToNum(String &str);
-  static String getFileSize(String &filename);
+  static size_t stringToNum(std::string &str);
+  static std::string getFileSize(std::string &filename);
 
 private:
-  String m_filename;
+  std::string m_filename;
   size_t m_filesize;
 };
diff --git a/src/lib/deskflow/DropHelper.cpp b/src/lib/deskflow/DropHelper.cpp
index ee55ef421..858887bb9 100644
--- a/src/lib/deskflow/DropHelper.cpp
+++ b/src/lib/deskflow/DropHelper.cpp
@@ -21,13 +21,13 @@
 
 #include <fstream>
 
-void DropHelper::writeToDir(const String &destination, DragFileList &fileList, String &data)
+void DropHelper::writeToDir(const std::string &destination, DragFileList &fileList, std::string &data)
 {
   LOG((CLOG_DEBUG "dropping file, files=%i target=%s", fileList.size(), destination.c_str()));
 
   if (!destination.empty() && fileList.size() > 0) {
     std::fstream file;
-    String dropTarget = destination;
+    std::string dropTarget = destination;
 #ifdef SYSAPI_WIN32
     dropTarget.append("\\");
 #else
diff --git a/src/lib/deskflow/DropHelper.h b/src/lib/deskflow/DropHelper.h
index d6576036b..1117d29c1 100644
--- a/src/lib/deskflow/DropHelper.h
+++ b/src/lib/deskflow/DropHelper.h
@@ -17,11 +17,10 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/DragInformation.h"
 
 class DropHelper
 {
 public:
-  static void writeToDir(const String &destination, DragFileList &fileList, String &data);
+  static void writeToDir(const std::string &destination, DragFileList &fileList, std::string &data);
 };
diff --git a/src/lib/deskflow/FileChunk.cpp b/src/lib/deskflow/FileChunk.cpp
index bcc2b2125..df8f11cca 100644
--- a/src/lib/deskflow/FileChunk.cpp
+++ b/src/lib/deskflow/FileChunk.cpp
@@ -19,6 +19,7 @@
 
 #include "base/Log.h"
 #include "base/Stopwatch.h"
+#include "base/String.h"
 #include "deskflow/ProtocolUtil.h"
 #include "deskflow/protocol_types.h"
 #include "io/IStream.h"
@@ -30,7 +31,7 @@ FileChunk::FileChunk(size_t size) : Chunk(size)
   m_dataSize = size - FILE_CHUNK_META_SIZE;
 }
 
-FileChunk *FileChunk::start(const String &size)
+FileChunk *FileChunk::start(const std::string &size)
 {
   size_t sizeLength = size.size();
   FileChunk *start = new FileChunk(sizeLength + FILE_CHUNK_META_SIZE);
@@ -63,11 +64,11 @@ FileChunk *FileChunk::end()
   return end;
 }
 
-int FileChunk::assemble(deskflow::IStream *stream, String &dataReceived, size_t &expectedSize)
+int FileChunk::assemble(deskflow::IStream *stream, std::string &dataReceived, size_t &expectedSize)
 {
   // parse
   UInt8 mark = 0;
-  String content;
+  std::string content;
   static size_t receivedDataSize;
   static double elapsedTime;
   static Stopwatch stopwatch;
@@ -130,7 +131,7 @@ int FileChunk::assemble(deskflow::IStream *stream, String &dataReceived, size_t
 
 void FileChunk::send(deskflow::IStream *stream, UInt8 mark, char *data, size_t dataSize)
 {
-  String chunk(data, dataSize);
+  std::string chunk(data, dataSize);
 
   switch (mark) {
   case kDataStart:
diff --git a/src/lib/deskflow/FileChunk.h b/src/lib/deskflow/FileChunk.h
index 38159445c..e5029d57f 100644
--- a/src/lib/deskflow/FileChunk.h
+++ b/src/lib/deskflow/FileChunk.h
@@ -17,10 +17,11 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/basic_types.h"
 #include "deskflow/Chunk.h"
 
+#include <string>
+
 #define FILE_CHUNK_META_SIZE 2
 
 namespace deskflow {
@@ -32,9 +33,9 @@ class FileChunk : public Chunk
 public:
   FileChunk(size_t size);
 
-  static FileChunk *start(const String &size);
+  static FileChunk *start(const std::string &size);
   static FileChunk *data(UInt8 *data, size_t dataSize);
   static FileChunk *end();
-  static int assemble(deskflow::IStream *stream, String &dataCached, size_t &expectedSize);
+  static int assemble(deskflow::IStream *stream, std::string &dataCached, size_t &expectedSize);
   static void send(deskflow::IStream *stream, UInt8 mark, char *data, size_t dataSize);
 };
diff --git a/src/lib/deskflow/IAppUtil.h b/src/lib/deskflow/IAppUtil.h
index 32236a4e5..ec5110e7c 100644
--- a/src/lib/deskflow/IAppUtil.h
+++ b/src/lib/deskflow/IAppUtil.h
@@ -18,10 +18,12 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/IInterface.h"
 #include "deskflow/IApp.h"
 
+#include <string>
+#include <vector>
+
 class IAppUtil : public IInterface
 {
 public:
@@ -30,7 +32,7 @@ public:
   virtual int run(int argc, char **argv) = 0;
   virtual void beforeAppExit() = 0;
   virtual void startNode() = 0;
-  virtual std::vector<String> getKeyboardLayoutList() = 0;
-  virtual String getCurrentLanguageCode() = 0;
-  virtual void showNotification(const String &title, const String &text) const = 0;
+  virtual std::vector<std::string> getKeyboardLayoutList() = 0;
+  virtual std::string getCurrentLanguageCode() = 0;
+  virtual void showNotification(const std::string &title, const std::string &text) const = 0;
 };
diff --git a/src/lib/deskflow/IClient.h b/src/lib/deskflow/IClient.h
index 234507d6f..cba1ecaaf 100644
--- a/src/lib/deskflow/IClient.h
+++ b/src/lib/deskflow/IClient.h
@@ -18,13 +18,14 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/IScreen.h"
 #include "deskflow/clipboard_types.h"
 #include "deskflow/key_types.h"
 #include "deskflow/mouse_types.h"
 #include "deskflow/option_types.h"
 
+#include <string>
+
 //! Client interface
 /*!
 This interface defines the methods necessary for the server to
@@ -86,14 +87,14 @@ public:
   synthesize an up or repeat for the same client key synthesized by
   keyDown().
   */
-  virtual void keyDown(KeyID id, KeyModifierMask, KeyButton, const String &) = 0;
+  virtual void keyDown(KeyID id, KeyModifierMask, KeyButton, const std::string &) = 0;
 
   //! Notify of key repeat
   /*!
   Synthesize key events to generate a press and release of key \c id
   \c count times.  If possible match the given modifier mask.
   */
-  virtual void keyRepeat(KeyID id, KeyModifierMask, SInt32 count, KeyButton, const String &lang) = 0;
+  virtual void keyRepeat(KeyID id, KeyModifierMask, SInt32 count, KeyButton, const std::string &lang) = 0;
 
   //! Notify of key release
   /*!
@@ -161,7 +162,7 @@ public:
   /*!
   Return the client's name.
   */
-  virtual String getName() const = 0;
+  virtual std::string getName() const = 0;
 
   //@}
 
diff --git a/src/lib/deskflow/IClipboard.cpp b/src/lib/deskflow/IClipboard.cpp
index 02a044d5b..e3d443588 100644
--- a/src/lib/deskflow/IClipboard.cpp
+++ b/src/lib/deskflow/IClipboard.cpp
@@ -23,7 +23,7 @@
 // IClipboard
 //
 
-void IClipboard::unmarshall(IClipboard *clipboard, const String &data, Time time)
+void IClipboard::unmarshall(IClipboard *clipboard, const std::string &data, Time time)
 {
   assert(clipboard != NULL);
 
@@ -51,7 +51,7 @@ void IClipboard::unmarshall(IClipboard *clipboard, const String &data, Time time
       // or server supports more clipboard formats than the other
       // then one of them will get a format >= kNumFormats here.
       if (format < IClipboard::kNumFormats) {
-        clipboard->add(format, String(index, size));
+        clipboard->add(format, std::string(index, size));
       }
       index += size;
     }
@@ -61,7 +61,7 @@ void IClipboard::unmarshall(IClipboard *clipboard, const String &data, Time time
   }
 }
 
-String IClipboard::marshall(const IClipboard *clipboard)
+std::string IClipboard::marshall(const IClipboard *clipboard)
 {
   // return data format:
   // 4 bytes => number of formats included
@@ -72,9 +72,9 @@ String IClipboard::marshall(const IClipboard *clipboard)
 
   assert(clipboard != NULL);
 
-  String data;
+  std::string data;
 
-  std::vector<String> formatData;
+  std::vector<std::string> formatData;
   formatData.resize(IClipboard::kNumFormats);
   // FIXME -- use current time
   if (clipboard->open(0)) {
@@ -148,7 +148,7 @@ UInt32 IClipboard::readUInt32(const char *buf)
          (static_cast<UInt32>(ubuf[2]) << 8) | static_cast<UInt32>(ubuf[3]);
 }
 
-void IClipboard::writeUInt32(String *buf, UInt32 v)
+void IClipboard::writeUInt32(std::string *buf, UInt32 v)
 {
   *buf += static_cast<UInt8>((v >> 24) & 0xff);
   *buf += static_cast<UInt8>((v >> 16) & 0xff);
diff --git a/src/lib/deskflow/IClipboard.h b/src/lib/deskflow/IClipboard.h
index 212125fa6..cc526c716 100644
--- a/src/lib/deskflow/IClipboard.h
+++ b/src/lib/deskflow/IClipboard.h
@@ -19,9 +19,10 @@
 #pragma once
 
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "common/IInterface.h"
 
+#include <string>
+
 //! Clipboard interface
 /*!
 This interface defines the methods common to all clipboards.
@@ -81,7 +82,7 @@ public:
   Add data in the given format to the clipboard.  May only be
   called after a successful empty().
   */
-  virtual void add(EFormat, const String &data) = 0;
+  virtual void add(EFormat, const std::string &data) = 0;
 
   //@}
   //! @name accessors
@@ -127,21 +128,21 @@ public:
   if there is no data in that format.  Must be called between
   a successful open() and close().
   */
-  virtual String get(EFormat) const = 0;
+  virtual std::string get(EFormat) const = 0;
 
   //! Marshall clipboard data
   /*!
   Merge \p clipboard's data into a single buffer that can be later
   unmarshalled to restore the clipboard and return the buffer.
   */
-  static String marshall(const IClipboard *clipboard);
+  static std::string marshall(const IClipboard *clipboard);
 
   //! Unmarshall clipboard data
   /*!
   Extract marshalled clipboard data and store it in \p clipboard.
   Sets the clipboard time to \c time.
   */
-  static void unmarshall(IClipboard *clipboard, const String &data, Time time);
+  static void unmarshall(IClipboard *clipboard, const std::string &data, Time time);
 
   //! Copy clipboard
   /*!
@@ -166,5 +167,5 @@ public:
 
 private:
   static UInt32 readUInt32(const char *);
-  static void writeUInt32(String *, UInt32);
+  static void writeUInt32(std::string *, UInt32);
 };
diff --git a/src/lib/deskflow/IKeyState.cpp b/src/lib/deskflow/IKeyState.cpp
index 01976f97a..d52522f89 100644
--- a/src/lib/deskflow/IKeyState.cpp
+++ b/src/lib/deskflow/IKeyState.cpp
@@ -47,10 +47,10 @@ IKeyState::KeyInfo *IKeyState::KeyInfo::alloc(KeyID id, KeyModifierMask mask, Ke
 }
 
 IKeyState::KeyInfo *IKeyState::KeyInfo::alloc(
-    KeyID id, KeyModifierMask mask, KeyButton button, SInt32 count, const std::set<String> &destinations
+    KeyID id, KeyModifierMask mask, KeyButton button, SInt32 count, const std::set<std::string> &destinations
 )
 {
-  String screens = join(destinations);
+  std::string screens = join(destinations);
   const char *buffer = screens.c_str();
 
   // build structure
@@ -82,7 +82,7 @@ bool IKeyState::KeyInfo::isDefault(const char *screens)
   return (screens == NULL || screens[0] == '\0');
 }
 
-bool IKeyState::KeyInfo::contains(const char *screens, const String &name)
+bool IKeyState::KeyInfo::contains(const char *screens, const std::string &name)
 {
   // special cases
   if (isDefault(screens)) {
@@ -93,7 +93,7 @@ bool IKeyState::KeyInfo::contains(const char *screens, const String &name)
   }
 
   // search
-  String match;
+  std::string match;
   match.reserve(name.size() + 2);
   match += ":";
   match += name;
@@ -109,12 +109,12 @@ bool IKeyState::KeyInfo::equal(const KeyInfo *a, const KeyInfo *b)
   );
 }
 
-String IKeyState::KeyInfo::join(const std::set<String> &destinations)
+std::string IKeyState::KeyInfo::join(const std::set<std::string> &destinations)
 {
   // collect destinations into a string.  names are surrounded by ':'
   // which makes searching easy.  the string is empty if there are no
   // destinations and "*" means all destinations.
-  String screens;
+  std::string screens;
   for (auto i = destinations.begin(); i != destinations.end(); ++i) {
     if (*i == "*") {
       screens = "*";
@@ -130,7 +130,7 @@ String IKeyState::KeyInfo::join(const std::set<String> &destinations)
   return screens;
 }
 
-void IKeyState::KeyInfo::split(const char *screens, std::set<String> &dst)
+void IKeyState::KeyInfo::split(const char *screens, std::set<std::string> &dst)
 {
   dst.clear();
   if (isDefault(screens)) {
@@ -144,7 +144,7 @@ void IKeyState::KeyInfo::split(const char *screens, std::set<String> &dst)
   const char *i = screens + 1;
   while (*i != '\0') {
     const char *j = strchr(i, ':');
-    dst.insert(String(i, j - i));
+    dst.insert(std::string(i, j - i));
     i = j + 1;
   }
 }
diff --git a/src/lib/deskflow/IKeyState.h b/src/lib/deskflow/IKeyState.h
index 0de9b265b..287cc03aa 100644
--- a/src/lib/deskflow/IKeyState.h
+++ b/src/lib/deskflow/IKeyState.h
@@ -21,7 +21,6 @@
 #include "base/Event.h"
 #include "base/EventTypes.h"
 #include "base/IEventQueue.h"
-#include "base/String.h"
 #include "common/IInterface.h"
 #include "common/stdset.h"
 #include "deskflow/key_types.h"
@@ -46,14 +45,14 @@ public:
   {
   public:
     static KeyInfo *alloc(KeyID, KeyModifierMask, KeyButton, SInt32 count);
-    static KeyInfo *alloc(KeyID, KeyModifierMask, KeyButton, SInt32 count, const std::set<String> &destinations);
+    static KeyInfo *alloc(KeyID, KeyModifierMask, KeyButton, SInt32 count, const std::set<std::string> &destinations);
     static KeyInfo *alloc(const KeyInfo &);
 
     static bool isDefault(const char *screens);
-    static bool contains(const char *screens, const String &name);
+    static bool contains(const char *screens, const std::string &name);
     static bool equal(const KeyInfo *, const KeyInfo *);
-    static String join(const std::set<String> &destinations);
-    static void split(const char *screens, std::set<String> &);
+    static std::string join(const std::set<std::string> &destinations);
+    static void split(const char *screens, std::set<std::string> &);
 
   public:
     KeyID m_key;
@@ -95,13 +94,14 @@ public:
   /*!
   Synthesizes a key press event and updates the key state.
   */
-  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang) = 0;
+  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang) = 0;
 
   //! Fake a key repeat
   /*!
   Synthesizes a key repeat event and updates the key state.
   */
-  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang) = 0;
+  virtual bool
+  fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang) = 0;
 
   //! Fake a key release
   /*!
diff --git a/src/lib/deskflow/IPlatformScreen.h b/src/lib/deskflow/IPlatformScreen.h
index 4c66bbba0..46502ba09 100644
--- a/src/lib/deskflow/IPlatformScreen.h
+++ b/src/lib/deskflow/IPlatformScreen.h
@@ -146,7 +146,7 @@ public:
   On MacOS check which app causes a secure input state to be enabled. No
   alternative on other platforms
   */
-  virtual String getSecureInputApp() const = 0;
+  virtual std::string getSecureInputApp() const = 0;
 
   //@}
   //! @name accessors
@@ -187,8 +187,9 @@ public:
   virtual void updateKeyMap() = 0;
   virtual void updateKeyState() = 0;
   virtual void setHalfDuplexMask(KeyModifierMask) = 0;
-  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang) = 0;
-  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang) = 0;
+  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang) = 0;
+  virtual bool
+  fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang) = 0;
   virtual bool fakeKeyUp(KeyButton button) = 0;
   virtual void fakeAllKeysUp() = 0;
   virtual bool fakeCtrlAltDel() = 0;
@@ -199,13 +200,13 @@ public:
   virtual SInt32 pollActiveGroup() const = 0;
   virtual void pollPressedKeys(KeyButtonSet &pressedKeys) const = 0;
 
-  virtual String &getDraggingFilename() = 0;
+  virtual std::string &getDraggingFilename() = 0;
   virtual void clearDraggingFilename() = 0;
   virtual bool isDraggingStarted() = 0;
   virtual bool isFakeDraggingStarted() = 0;
 
   virtual void fakeDraggingFiles(DragFileList fileList) = 0;
-  virtual const String &getDropTarget() const = 0;
+  virtual const std::string &getDropTarget() const = 0;
 
 protected:
   //! Handle system event
diff --git a/src/lib/deskflow/KeyMap.cpp b/src/lib/deskflow/KeyMap.cpp
index d80d84934..92009101a 100644
--- a/src/lib/deskflow/KeyMap.cpp
+++ b/src/lib/deskflow/KeyMap.cpp
@@ -243,7 +243,7 @@ void KeyMap::foreachKey(ForeachKeyCallback cb, void *userData)
 
 const KeyMap::KeyItem *KeyMap::mapKey(
     Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-    KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+    KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
 ) const
 {
   LOG(
@@ -310,12 +310,12 @@ const KeyMap::KeyItem *KeyMap::mapKey(
   return item;
 }
 
-void KeyMap::setLanguageData(std::vector<String> layouts)
+void KeyMap::setLanguageData(std::vector<std::string> layouts)
 {
   m_keyboardLayouts = std::move(layouts);
 }
 
-SInt32 KeyMap::getLanguageGroupID(SInt32 group, const String &lang) const
+SInt32 KeyMap::getLanguageGroupID(SInt32 group, const std::string &lang) const
 {
   SInt32 id = group;
 
@@ -488,7 +488,7 @@ void KeyMap::setModifierKeys()
 
 const KeyMap::KeyItem *KeyMap::mapCommandKey(
     Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-    KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+    KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
 ) const
 {
   static const KeyModifierMask s_overrideModifiers = 0xffffu;
@@ -591,7 +591,7 @@ KeyMap::getKeyItemList(const KeyMap::KeyGroupTable &keyGroupTable, SInt32 group,
 
 const KeyMap::KeyItem *KeyMap::mapCharacterKey(
     Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-    KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+    KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
 ) const
 {
   // find KeySym in table
@@ -641,7 +641,7 @@ const KeyMap::KeyItem *KeyMap::mapCharacterKey(
   return &keyItem;
 }
 
-void KeyMap::addGroupToKeystroke(Keystrokes &keys, SInt32 &group, const String &lang) const
+void KeyMap::addGroupToKeystroke(Keystrokes &keys, SInt32 &group, const std::string &lang) const
 {
   group = getLanguageGroupID(group, lang);
   keys.push_back(Keystroke(group, true, false));
@@ -649,7 +649,7 @@ void KeyMap::addGroupToKeystroke(Keystrokes &keys, SInt32 &group, const String &
 
 const KeyMap::KeyItem *KeyMap::mapModifierKey(
     Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-    KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+    KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
 ) const
 {
   return mapCharacterKey(keys, id, group, activeModifiers, currentState, desiredMask, isAutoRepeat, lang);
@@ -708,7 +708,7 @@ const KeyMap::KeyItem *KeyMap::keyForModifier(KeyButton button, SInt32 group, SI
 bool KeyMap::keysForKeyItem(
     const KeyItem &keyItem, SInt32 &group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
     KeyModifierMask desiredState, KeyModifierMask overrideModifiers, bool isAutoRepeat, Keystrokes &keystrokes,
-    const String &lang
+    const std::string &lang
 ) const
 {
   static const KeyModifierMask s_notRequiredMask = KeyModifierAltGr | KeyModifierNumLock | KeyModifierScrollLock;
@@ -1090,12 +1090,12 @@ KeyID KeyMap::getDeadKey(KeyID key)
   }
 }
 
-String KeyMap::formatKey(KeyID key, KeyModifierMask mask)
+std::string KeyMap::formatKey(KeyID key, KeyModifierMask mask)
 {
   // initialize tables
   initKeyNameMaps();
 
-  String x;
+  std::string x;
   for (SInt32 i = 0; i < kKeyModifierNumBits; ++i) {
     KeyModifierMask mod = (1u << i);
     if ((mask & mod) != 0 && s_modifierToNameMap->count(mod) > 0) {
@@ -1120,7 +1120,7 @@ String KeyMap::formatKey(KeyID key, KeyModifierMask mask)
   return x;
 }
 
-bool KeyMap::parseKey(const String &x, KeyID &key)
+bool KeyMap::parseKey(const std::string &x, KeyID &key)
 {
   // initialize tables
   initKeyNameMaps();
@@ -1152,20 +1152,20 @@ bool KeyMap::parseKey(const String &x, KeyID &key)
   return true;
 }
 
-bool KeyMap::parseModifiers(String &x, KeyModifierMask &mask)
+bool KeyMap::parseModifiers(std::string &x, KeyModifierMask &mask)
 {
   // initialize tables
   initKeyNameMaps();
 
   mask = 0;
-  String::size_type tb = x.find_first_not_of(" \t", 0);
-  while (tb != String::npos) {
+  std::string::size_type tb = x.find_first_not_of(" \t", 0);
+  while (tb != std::string::npos) {
     // get next component
-    String::size_type te = x.find_first_of(" \t+)", tb);
-    if (te == String::npos) {
+    std::string::size_type te = x.find_first_of(" \t+)", tb);
+    if (te == std::string::npos) {
       te = x.size();
     }
-    String c = x.substr(tb, te - tb);
+    std::string c = x.substr(tb, te - tb);
     if (c.empty()) {
       // missing component
       return false;
@@ -1181,9 +1181,9 @@ bool KeyMap::parseModifiers(String &x, KeyModifierMask &mask)
     } else {
       // unknown string
       x.erase(0, tb);
-      String::size_type tb = x.find_first_not_of(" \t");
-      String::size_type te = x.find_last_not_of(" \t");
-      if (tb == String::npos) {
+      std::string::size_type tb = x.find_first_not_of(" \t");
+      std::string::size_type te = x.find_last_not_of(" \t");
+      if (tb == std::string::npos) {
         x = "";
       } else {
         x = x.substr(tb, te - tb + 1);
@@ -1193,7 +1193,7 @@ bool KeyMap::parseModifiers(String &x, KeyModifierMask &mask)
 
     // check for '+' or end of string
     tb = x.find_first_not_of(" \t", te);
-    if (tb != String::npos) {
+    if (tb != std::string::npos) {
       if (x[tb] != '+') {
         // expected '+'
         return false;
diff --git a/src/lib/deskflow/KeyMap.h b/src/lib/deskflow/KeyMap.h
index 0cc49a3a1..ca935c7cb 100644
--- a/src/lib/deskflow/KeyMap.h
+++ b/src/lib/deskflow/KeyMap.h
@@ -225,10 +225,10 @@ public:
   */
   virtual const KeyItem *mapKey(
       Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-      KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
   ) const;
 
-  void setLanguageData(std::vector<String> layouts);
+  void setLanguageData(std::vector<std::string> layouts);
 
   //! Get number of groups
   /*!
@@ -310,14 +310,14 @@ public:
   Converts a key and modifier mask into a string representing the
   combination.
   */
-  static String formatKey(KeyID key, KeyModifierMask);
+  static std::string formatKey(KeyID key, KeyModifierMask);
 
   //! Parse a string into a key
   /*!
   Converts a string into a key.  Returns \c true on success and \c false
   if the string cannot be parsed.
   */
-  static bool parseKey(const String &, KeyID &);
+  static bool parseKey(const std::string &, KeyID &);
 
   //! Parse a string into a modifier mask
   /*!
@@ -326,7 +326,7 @@ public:
   remaining leading and trailing whitespace is stripped from the input
   string.
   */
-  static bool parseModifiers(String &, KeyModifierMask &);
+  static bool parseModifiers(std::string &, KeyModifierMask &);
 
   //@}
 
@@ -369,7 +369,7 @@ private:
   // entries since they don't make sense as hotkeys.
   const KeyItem *mapCommandKey(
       Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-      KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
   ) const;
 
   // maps a character key.  a character key is trying to synthesize a
@@ -377,13 +377,13 @@ private:
   // used to do it.
   const KeyItem *mapCharacterKey(
       Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-      KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
   ) const;
 
   // maps a modifier key
   const KeyItem *mapModifierKey(
       Keystrokes &keys, KeyID id, SInt32 group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
-      KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+      KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
   ) const;
 
   // returns the index into \p entryList of the KeyItemList requiring
@@ -403,7 +403,7 @@ private:
   bool keysForKeyItem(
       const KeyItem &keyItem, SInt32 &group, ModifierToKeys &activeModifiers, KeyModifierMask &currentState,
       KeyModifierMask desiredState, KeyModifierMask overrideModifiers, bool isAutoRepeat, Keystrokes &keystrokes,
-      const String &lang
+      const std::string &lang
   ) const;
 
   // fills \p keystrokes with the keys to synthesize the modifiers
@@ -442,9 +442,9 @@ private:
   // Ways to synthesize a KeyID over multiple keyboard groups
   using KeyGroupTable = std::vector<KeyEntryList>;
 
-  void addGroupToKeystroke(Keystrokes &keys, SInt32 &group, const String &lang) const;
+  void addGroupToKeystroke(Keystrokes &keys, SInt32 &group, const std::string &lang) const;
 
-  SInt32 getLanguageGroupID(SInt32 group, const String &lang) const;
+  SInt32 getLanguageGroupID(SInt32 group, const std::string &lang) const;
   const KeyItemList *
   getKeyItemList(const KeyGroupTable &keyGroupTable, SInt32 group, KeyModifierMask desiredMask) const;
 
@@ -469,10 +469,10 @@ private:
   using KeyButtonSet = std::set<KeyButton>;
 
   // Key maps for parsing/formatting
-  using NameToKeyMap = std::map<String, KeyID, deskflow::string::CaselessCmp>;
-  using NameToModifierMap = std::map<String, KeyModifierMask, deskflow::string::CaselessCmp>;
-  using KeyToNameMap = std::map<KeyID, String>;
-  using ModifierToNameMap = std::map<KeyModifierMask, String>;
+  using NameToKeyMap = std::map<std::string, KeyID, deskflow::string::CaselessCmp>;
+  using NameToModifierMap = std::map<std::string, KeyModifierMask, deskflow::string::CaselessCmp>;
+  using KeyToNameMap = std::map<KeyID, std::string>;
+  using ModifierToNameMap = std::map<KeyModifierMask, std::string>;
 
   // KeyID info
   KeyIDMap m_keyIDMap;
@@ -490,7 +490,7 @@ private:
   KeyItem m_modifierKeyItem;
 
   // Language sync data
-  std::vector<String> m_keyboardLayouts;
+  std::vector<std::string> m_keyboardLayouts;
 
   // parsing/formatting tables
   static NameToKeyMap *s_nameToKeyMap;
diff --git a/src/lib/deskflow/KeyState.cpp b/src/lib/deskflow/KeyState.cpp
index b3dc5d914..c31c7da39 100644
--- a/src/lib/deskflow/KeyState.cpp
+++ b/src/lib/deskflow/KeyState.cpp
@@ -653,7 +653,7 @@ static const KeyID s_numpadTable[] = {
 // KeyState
 //
 
-KeyState::KeyState(IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled)
+KeyState::KeyState(IEventQueue *events, std::vector<std::string> layouts, bool isLangSyncEnabled)
     : IKeyState(events),
       m_keyMapPtr(new deskflow::KeyMap()),
       m_keyMap(*m_keyMapPtr),
@@ -665,7 +665,9 @@ KeyState::KeyState(IEventQueue *events, std::vector<String> layouts, bool isLang
   init();
 }
 
-KeyState::KeyState(IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<String> layouts, bool isLangSyncEnabled)
+KeyState::KeyState(
+    IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<std::string> layouts, bool isLangSyncEnabled
+)
     : IKeyState(events),
       m_keyMapPtr(0),
       m_keyMap(keyMap),
@@ -801,7 +803,7 @@ void KeyState::setHalfDuplexMask(KeyModifierMask mask)
   }
 }
 
-void KeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton serverID, const String &lang)
+void KeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton serverID, const std::string &lang)
 {
   // if this server key is already down then this is probably a
   // mis-reported autorepeat.
@@ -848,7 +850,7 @@ void KeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton serverID, c
   fakeKeys(keys, 1);
 }
 
-bool KeyState::fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton serverID, const String &lang)
+bool KeyState::fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton serverID, const std::string &lang)
 {
   LOG((CLOG_DEBUG2 "fakeKeyRepeat"));
   serverID &= kButtonMask;
diff --git a/src/lib/deskflow/KeyState.h b/src/lib/deskflow/KeyState.h
index 71bafa1dd..f2376edae 100644
--- a/src/lib/deskflow/KeyState.h
+++ b/src/lib/deskflow/KeyState.h
@@ -29,8 +29,8 @@ platform specific methods.
 class KeyState : public IKeyState
 {
 public:
-  KeyState(IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled);
-  KeyState(IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<String> layouts, bool isLangSyncEnabled);
+  KeyState(IEventQueue *events, std::vector<std::string> layouts, bool isLangSyncEnabled);
+  KeyState(IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<std::string> layouts, bool isLangSyncEnabled);
   virtual ~KeyState();
 
   //! @name manipulators
@@ -69,8 +69,8 @@ public:
   }
   void updateKeyState() override;
   void setHalfDuplexMask(KeyModifierMask) override;
-  void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang) override;
-  bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang) override;
+  void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang) override;
+  bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang) override;
   bool fakeKeyUp(KeyButton button) override;
   void fakeAllKeysUp() override;
   bool fakeMediaKey(KeyID id) override;
diff --git a/src/lib/deskflow/PlatformScreen.cpp b/src/lib/deskflow/PlatformScreen.cpp
index 7046ce300..9d2c288b3 100644
--- a/src/lib/deskflow/PlatformScreen.cpp
+++ b/src/lib/deskflow/PlatformScreen.cpp
@@ -49,12 +49,14 @@ void PlatformScreen::setHalfDuplexMask(KeyModifierMask mask)
   getKeyState()->setHalfDuplexMask(mask);
 }
 
-void PlatformScreen::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang)
+void PlatformScreen::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   getKeyState()->fakeKeyDown(id, mask, button, lang);
 }
 
-bool PlatformScreen::fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+bool PlatformScreen::fakeKeyRepeat(
+    KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang
+)
 {
   return getKeyState()->fakeKeyRepeat(id, mask, count, button, lang);
 }
diff --git a/src/lib/deskflow/PlatformScreen.h b/src/lib/deskflow/PlatformScreen.h
index 69e65ffeb..da9e00ef2 100644
--- a/src/lib/deskflow/PlatformScreen.h
+++ b/src/lib/deskflow/PlatformScreen.h
@@ -64,8 +64,8 @@ public:
   virtual void updateKeyMap();
   virtual void updateKeyState();
   virtual void setHalfDuplexMask(KeyModifierMask);
-  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &);
-  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang);
+  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &);
+  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang);
   virtual bool fakeKeyUp(KeyButton button);
   virtual void fakeAllKeysUp();
   virtual bool fakeCtrlAltDel();
@@ -84,7 +84,7 @@ public:
   {
     return m_fakeDraggingStarted;
   }
-  virtual String &getDraggingFilename()
+  virtual std::string &getDraggingFilename()
   {
     return m_draggingFilename;
   }
@@ -112,7 +112,7 @@ public:
   {
     throw std::runtime_error("fakeDraggingFiles not implemented");
   }
-  virtual const String &getDropTarget() const
+  virtual const std::string &getDropTarget() const
   {
     throw std::runtime_error("getDropTarget not implemented");
   }
@@ -143,7 +143,7 @@ protected:
   virtual SInt32 mapClientScrollDirection(SInt32) const;
 
 protected:
-  String m_draggingFilename;
+  std::string m_draggingFilename;
   bool m_draggingStarted;
   bool m_fakeDraggingStarted;
 
diff --git a/src/lib/deskflow/ProtocolUtil.cpp b/src/lib/deskflow/ProtocolUtil.cpp
index 5fbb9c729..6996c003a 100644
--- a/src/lib/deskflow/ProtocolUtil.cpp
+++ b/src/lib/deskflow/ProtocolUtil.cpp
@@ -67,7 +67,7 @@ template <typename T> void writeVectorInt(const std::vector<T> *VectorData, std:
   }
 }
 
-void writeString(const String *StringData, std::vector<UInt8> &Buffer)
+void writeString(const std::string *StringData, std::vector<UInt8> &Buffer)
 {
   const UInt32 len = (StringData != NULL) ? (UInt32)StringData->size() : 0;
   writeInt(len, sizeof(len), Buffer);
@@ -200,7 +200,7 @@ void ProtocolUtil::vreadf(deskflow::IStream *stream, const char *fmt, va_list ar
       }
 
       case 's': {
-        String *destination = va_arg(args, String *);
+        std::string *destination = va_arg(args, std::string *);
 
         if (len > PROTOCOL_MAX_STRING_LENGTH) {
           LOG((CLOG_ERR "read: string length exceeds maximum allowed size: %u", len));
@@ -271,7 +271,7 @@ UInt32 ProtocolUtil::getLength(const char *fmt, va_list args)
 
       case 's':
         assert(len == 0);
-        len = (UInt32)(va_arg(args, String *))->size() + 4;
+        len = (UInt32)(va_arg(args, std::string *))->size() + 4;
         break;
 
       case 'S':
@@ -346,7 +346,7 @@ void ProtocolUtil::writef(std::vector<UInt8> &buffer, const char *fmt, va_list a
 
       case 's': {
         assert(len == 0);
-        const String *src = va_arg(args, String *);
+        const std::string *src = va_arg(args, std::string *);
         writeString(src, buffer);
         break;
       }
@@ -520,7 +520,7 @@ UInt32 ProtocolUtil::readVectorSize(deskflow::IStream *stream)
   return size;
 }
 
-void ProtocolUtil::readBytes(deskflow::IStream *stream, UInt32 len, String *destination)
+void ProtocolUtil::readBytes(deskflow::IStream *stream, UInt32 len, std::string *destination)
 {
   // read the string length
   UInt8 buffer[128];
@@ -575,7 +575,7 @@ void ProtocolUtil::readBytes(deskflow::IStream *stream, UInt32 len, String *dest
 // XIOReadMismatch
 //
 
-String XIOReadMismatch::getWhat() const throw()
+std::string XIOReadMismatch::getWhat() const throw()
 {
   return format("XIOReadMismatch", "ProtocolUtil::readf() mismatch");
 }
diff --git a/src/lib/deskflow/ProtocolUtil.h b/src/lib/deskflow/ProtocolUtil.h
index 60b436d99..4ad75a578 100644
--- a/src/lib/deskflow/ProtocolUtil.h
+++ b/src/lib/deskflow/ProtocolUtil.h
@@ -22,6 +22,7 @@
 #include "io/XIO.h"
 
 #include <stdarg.h>
+#include <vector>
 
 namespace deskflow {
 class IStream;
@@ -50,7 +51,7 @@ public:
   - \%1I  -- converts std::vector<UInt8>* to 1 byte integers
   - \%2I  -- converts std::vector<UInt16>* to 2 byte integers in NBO
   - \%4I  -- converts std::vector<UInt32>* to 4 byte integers in NBO
-  - \%s   -- converts String* to stream of bytes
+  - \%s   -- converts std::string* to stream of bytes
   - \%S   -- converts integer N and const UInt8* to stream of N bytes
   */
   static void writef(deskflow::IStream *, const char *fmt, ...);
@@ -69,7 +70,7 @@ public:
   - \%1I  -- reads 1 byte integers;  arg is std::vector<UInt8>*
   - \%2I  -- reads NBO 2 byte integers;  arg is std::vector<UInt16>*
   - \%4I  -- reads NBO 4 byte integers;  arg is std::vector<UInt32>*
-  - \%s   -- reads bytes;  argument must be a String*, \b not a char*
+  - \%s   -- reads bytes;  argument must be a std::string*, \b not a char*
   */
   static bool readf(deskflow::IStream *, const char *fmt, ...);
 
@@ -100,7 +101,7 @@ private:
   /**
    * @brief Handles an array of bytes
    */
-  static void readBytes(deskflow::IStream *, UInt32, String *);
+  static void readBytes(deskflow::IStream *, UInt32, std::string *);
 };
 
 //! Mismatched read exception
@@ -112,5 +113,5 @@ class XIOReadMismatch : public XIO
 {
 public:
   // XBase overrides
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 };
diff --git a/src/lib/deskflow/Screen.cpp b/src/lib/deskflow/Screen.cpp
index f3581201c..3b4523b9f 100644
--- a/src/lib/deskflow/Screen.cpp
+++ b/src/lib/deskflow/Screen.cpp
@@ -198,7 +198,7 @@ void Screen::screensaver(bool) const
   // do nothing
 }
 
-void Screen::keyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang)
+void Screen::keyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   // check for ctrl+alt+del emulation
   if (id == kKeyDelete && (mask & (KeyModifierControl | KeyModifierAlt)) == (KeyModifierControl | KeyModifierAlt)) {
@@ -210,7 +210,7 @@ void Screen::keyDown(KeyID id, KeyModifierMask mask, KeyButton button, const Str
   m_screen->fakeKeyDown(id, mask, button, lang);
 }
 
-void Screen::keyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+void Screen::keyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang)
 {
   assert(!m_isPrimary);
   m_screen->fakeKeyRepeat(id, mask, count, button, lang);
@@ -400,7 +400,7 @@ void Screen::setEnableDragDrop(bool enabled)
   m_enableDragDrop = enabled;
 }
 
-String &Screen::getDraggingFilename() const
+std::string &Screen::getDraggingFilename() const
 {
   return m_screen->getDraggingFilename();
 }
@@ -410,7 +410,7 @@ void Screen::clearDraggingFilename()
   m_screen->clearDraggingFilename();
 }
 
-const String &Screen::getDropTarget() const
+const std::string &Screen::getDropTarget() const
 {
   return m_screen->getDropTarget();
 }
@@ -488,7 +488,7 @@ void Screen::leaveSecondary()
   m_screen->fakeAllKeysUp();
 }
 
-String Screen::getSecureInputApp() const
+std::string Screen::getSecureInputApp() const
 {
   return m_screen->getSecureInputApp();
 }
diff --git a/src/lib/deskflow/Screen.h b/src/lib/deskflow/Screen.h
index 9e4c3ef63..21dec5e82 100644
--- a/src/lib/deskflow/Screen.h
+++ b/src/lib/deskflow/Screen.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/DragInformation.h"
 #include "deskflow/IScreen.h"
 #include "deskflow/clipboard_types.h"
@@ -130,14 +129,14 @@ public:
   synthesize an up or repeat for the same client key synthesized by
   keyDown().
   */
-  void keyDown(KeyID id, KeyModifierMask, KeyButton, const String &);
+  void keyDown(KeyID id, KeyModifierMask, KeyButton, const std::string &);
 
   //! Notify of key repeat
   /*!
   Synthesize key events to generate a press and release of key \c id
   \c count times.  If possible match the given modifier mask.
   */
-  void keyRepeat(KeyID id, KeyModifierMask, SInt32 count, KeyButton, const String &lang);
+  void keyRepeat(KeyID id, KeyModifierMask, SInt32 count, KeyButton, const std::string &lang);
 
   //! Notify of key release
   /*!
@@ -241,7 +240,7 @@ public:
   On MacOS check which app causes a secure input state to be enabled. No
   alternative on other platforms
   */
-  String getSecureInputApp() const;
+  std::string getSecureInputApp() const;
 
   //@}
   //! @name accessors
@@ -298,13 +297,13 @@ public:
   bool isFakeDraggingStarted() const;
 
   //! Get the filename of the file being dragged
-  String &getDraggingFilename() const;
+  std::string &getDraggingFilename() const;
 
   //! Clear the filename of the file that was dragged
   void clearDraggingFilename();
 
   //! Get the drop target directory
-  const String &getDropTarget() const;
+  const std::string &getDropTarget() const;
 
   //@}
 
diff --git a/src/lib/deskflow/ServerApp.cpp b/src/lib/deskflow/ServerApp.cpp
index fef215393..73b764fd1 100644
--- a/src/lib/deskflow/ServerApp.cpp
+++ b/src/lib/deskflow/ServerApp.cpp
@@ -236,7 +236,7 @@ void ServerApp::loadConfig()
   }
 }
 
-bool ServerApp::loadConfig(const String &pathname)
+bool ServerApp::loadConfig(const std::string &pathname)
 {
   try {
     // load configuration
@@ -325,7 +325,7 @@ void ServerApp::updateStatus()
   updateStatus("");
 }
 
-void ServerApp::updateStatus(const String &msg)
+void ServerApp::updateStatus(const std::string &msg)
 {
   if (m_taskBarReceiver) {
     m_taskBarReceiver->updateStatus(m_server, msg);
@@ -445,7 +445,7 @@ bool ServerApp::initServer()
   deskflow::Screen *serverScreen = NULL;
   PrimaryClient *primaryClient = NULL;
   try {
-    String name = args().m_config->getCanonicalName(args().m_name);
+    std::string name = args().m_config->getCanonicalName(args().m_name);
     serverScreen = openServerScreen();
     primaryClient = openPrimaryClient(name, serverScreen);
     m_serverScreen = serverScreen;
@@ -457,7 +457,7 @@ bool ServerApp::initServer()
     LOG((CLOG_WARN "primary screen unavailable: %s", e.what()));
     closePrimaryClient(primaryClient);
     closeServerScreen(serverScreen);
-    updateStatus(String("primary screen unavailable: ") + e.what());
+    updateStatus(std::string("primary screen unavailable: ") + e.what());
     retryTime = e.getRetryTime();
   } catch (XScreenOpenFailure &e) {
     LOG((CLOG_CRIT "failed to start server: %s", e.what()));
@@ -543,7 +543,7 @@ bool ServerApp::startServer()
       LOG((CLOG_CRIT "cannot listen for clients: %s", e.what()));
     }
     closeClientListener(listener);
-    updateStatus(String("cannot listen for clients: ") + e.what());
+    updateStatus(std::string("cannot listen for clients: ") + e.what());
   } catch (XBase &e) {
     LOG((CLOG_CRIT "failed to start server: %s", e.what()));
     closeClientListener(listener);
@@ -594,7 +594,7 @@ deskflow::Screen *ServerApp::createScreen()
 #endif
 }
 
-PrimaryClient *ServerApp::openPrimaryClient(const String &name, deskflow::Screen *screen)
+PrimaryClient *ServerApp::openPrimaryClient(const std::string &name, deskflow::Screen *screen)
 {
   LOG((CLOG_DEBUG1 "creating primary screen"));
   return new PrimaryClient(name, screen);
@@ -714,7 +714,7 @@ int ServerApp::mainLoop()
   }
 
   // canonicalize the primary screen name
-  String primaryName = args().m_config->getCanonicalName(args().m_name);
+  std::string primaryName = args().m_config->getCanonicalName(args().m_name);
   if (primaryName.empty()) {
     LOG((CLOG_CRIT "unknown screen name `%s'", args().m_name.c_str()));
     return kExitFailed;
diff --git a/src/lib/deskflow/ServerApp.h b/src/lib/deskflow/ServerApp.h
index 728b73220..a7b58ec54 100644
--- a/src/lib/deskflow/ServerApp.h
+++ b/src/lib/deskflow/ServerApp.h
@@ -68,7 +68,7 @@ public:
   const char *daemonName() const override;
   const char *daemonInfo() const override;
   void loadConfig() override;
-  bool loadConfig(const String &pathname) override;
+  bool loadConfig(const std::string &pathname) override;
   deskflow::Screen *createScreen() override;
   int mainLoop() override;
   int runInner(int argc, char **argv, ILogOutputter *outputter, StartupFunc startup) override;
@@ -97,7 +97,7 @@ public:
   void closeServer(Server *server);
   void stopRetryTimer();
   void updateStatus();
-  void updateStatus(const String &msg);
+  void updateStatus(const std::string &msg);
   void closeClientListener(ClientListener *listen);
   void stopServer();
   void closePrimaryClient(PrimaryClient *primaryClient);
@@ -106,7 +106,7 @@ public:
   bool initServer();
   void retryHandler(const Event &, void *);
   deskflow::Screen *openServerScreen();
-  PrimaryClient *openPrimaryClient(const String &name, deskflow::Screen *screen);
+  PrimaryClient *openPrimaryClient(const std::string &name, deskflow::Screen *screen);
   void handleScreenError(const Event &, void *);
   void handleSuspend(const Event &, void *);
   void handleResume(const Event &, void *);
diff --git a/src/lib/deskflow/ServerArgs.h b/src/lib/deskflow/ServerArgs.h
index f01c2377b..54d5e2b04 100644
--- a/src/lib/deskflow/ServerArgs.h
+++ b/src/lib/deskflow/ServerArgs.h
@@ -38,7 +38,7 @@ public:
   ServerArgs &operator=(ServerArgs &&) = default;
 
 public:
-  String m_configFile = "";
+  std::string m_configFile = "";
   std::shared_ptr<Config> m_config;
 };
 
diff --git a/src/lib/deskflow/ServerTaskBarReceiver.cpp b/src/lib/deskflow/ServerTaskBarReceiver.cpp
index 3fdfd4aee..08c5908b7 100644
--- a/src/lib/deskflow/ServerTaskBarReceiver.cpp
+++ b/src/lib/deskflow/ServerTaskBarReceiver.cpp
@@ -38,7 +38,7 @@ ServerTaskBarReceiver::~ServerTaskBarReceiver()
   // do nothing
 }
 
-void ServerTaskBarReceiver::updateStatus(Server *server, const String &errorMsg)
+void ServerTaskBarReceiver::updateStatus(Server *server, const std::string &errorMsg)
 {
   {
     // update our status
@@ -72,7 +72,7 @@ ServerTaskBarReceiver::EState ServerTaskBarReceiver::getStatus() const
   return m_state;
 }
 
-const String &ServerTaskBarReceiver::getErrorMessage() const
+const std::string &ServerTaskBarReceiver::getErrorMessage() const
 {
   return m_errorMessage;
 }
diff --git a/src/lib/deskflow/ServerTaskBarReceiver.h b/src/lib/deskflow/ServerTaskBarReceiver.h
index 5ae86dab6..c83b58d5b 100644
--- a/src/lib/deskflow/ServerTaskBarReceiver.h
+++ b/src/lib/deskflow/ServerTaskBarReceiver.h
@@ -21,7 +21,6 @@
 #include "arch/IArchTaskBarReceiver.h"
 #include "base/Event.h"
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "common/stdvector.h"
 #include "deskflow/ServerApp.h"
 #include "server/Server.h"
@@ -42,9 +41,9 @@ public:
   /*!
   Determine the status and query required information from the server.
   */
-  void updateStatus(Server *, const String &errorMsg);
+  void updateStatus(Server *, const std::string &errorMsg);
 
-  void updateStatus(INode *n, const String &errorMsg)
+  void updateStatus(INode *n, const std::string &errorMsg)
   {
     updateStatus((Server *)n, errorMsg);
   }
@@ -61,7 +60,7 @@ public:
   virtual std::string getToolTip() const;
 
 protected:
-  using Clients = std::vector<String>;
+  using Clients = std::vector<std::string>;
   enum EState
   {
     kNotRunning,
@@ -75,7 +74,7 @@ protected:
   EState getStatus() const;
 
   //! Get error message
-  const String &getErrorMessage() const;
+  const std::string &getErrorMessage() const;
 
   //! Get connected clients
   const Clients &getClients() const;
@@ -95,7 +94,7 @@ protected:
 
 private:
   EState m_state;
-  String m_errorMessage;
+  std::string m_errorMessage;
   Clients m_clients;
   IEventQueue *m_events;
 };
diff --git a/src/lib/deskflow/StreamChunker.cpp b/src/lib/deskflow/StreamChunker.cpp
index f4e0980ec..4c5491428 100644
--- a/src/lib/deskflow/StreamChunker.cpp
+++ b/src/lib/deskflow/StreamChunker.cpp
@@ -55,7 +55,7 @@ void StreamChunker::sendFile(char *filename, IEventQueue *events, void *eventTar
   size_t size = (size_t)file.tellg();
 
   // send first message (file size)
-  String fileSize = deskflow::string::sizeTypeToString(size);
+  std::string fileSize = deskflow::string::sizeTypeToString(size);
   FileChunk *sizeMessage = FileChunk::start(fileSize);
 
   events->addEvent(Event(events->forFile().fileChunkSending(), eventTarget, sizeMessage));
@@ -106,11 +106,11 @@ void StreamChunker::sendFile(char *filename, IEventQueue *events, void *eventTar
 }
 
 void StreamChunker::sendClipboard(
-    String &data, size_t size, ClipboardID id, UInt32 sequence, IEventQueue *events, void *eventTarget
+    std::string &data, size_t size, ClipboardID id, UInt32 sequence, IEventQueue *events, void *eventTarget
 )
 {
   // send first message (data size)
-  String dataSize = deskflow::string::sizeTypeToString(size);
+  std::string dataSize = deskflow::string::sizeTypeToString(size);
   ClipboardChunk *sizeMessage = ClipboardChunk::start(id, sequence, dataSize);
 
   events->addEvent(Event(events->forClipboard().clipboardSending(), eventTarget, sizeMessage));
@@ -127,7 +127,7 @@ void StreamChunker::sendClipboard(
       chunkSize = size - sentLength;
     }
 
-    String chunk(data.substr(sentLength, chunkSize).c_str(), chunkSize);
+    std::string chunk(data.substr(sentLength, chunkSize).c_str(), chunkSize);
     ClipboardChunk *dataChunk = ClipboardChunk::data(id, sequence, chunk);
 
     events->addEvent(Event(events->forClipboard().clipboardSending(), eventTarget, dataChunk));
diff --git a/src/lib/deskflow/StreamChunker.h b/src/lib/deskflow/StreamChunker.h
index 9b12f21c7..07980279a 100644
--- a/src/lib/deskflow/StreamChunker.h
+++ b/src/lib/deskflow/StreamChunker.h
@@ -17,9 +17,10 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/clipboard_types.h"
 
+#include <string>
+
 class IEventQueue;
 class Mutex;
 
@@ -27,8 +28,9 @@ class StreamChunker
 {
 public:
   static void sendFile(char *filename, IEventQueue *events, void *eventTarget);
-  static void
-  sendClipboard(String &data, size_t size, ClipboardID id, UInt32 sequence, IEventQueue *events, void *eventTarget);
+  static void sendClipboard(
+      std::string &data, size_t size, ClipboardID id, UInt32 sequence, IEventQueue *events, void *eventTarget
+  );
   static void interruptFile();
 
 private:
diff --git a/src/lib/deskflow/XDeskflow.cpp b/src/lib/deskflow/XDeskflow.cpp
index f8aa52ba5..ca4afc92f 100644
--- a/src/lib/deskflow/XDeskflow.cpp
+++ b/src/lib/deskflow/XDeskflow.cpp
@@ -23,7 +23,7 @@
 // XBadClient
 //
 
-String XBadClient::getWhat() const throw()
+std::string XBadClient::getWhat() const throw()
 {
   return "XBadClient";
 }
@@ -32,7 +32,7 @@ String XBadClient::getWhat() const throw()
 // XInvalidProtocol
 //
 
-String XInvalidProtocol::getWhat() const throw()
+std::string XInvalidProtocol::getWhat() const throw()
 {
   return "XInvalidProtocol";
 }
@@ -56,7 +56,7 @@ int XIncompatibleClient::getMinor() const throw()
   return m_minor;
 }
 
-String XIncompatibleClient::getWhat() const throw()
+std::string XIncompatibleClient::getWhat() const throw()
 {
   return format(
       "XIncompatibleClient", "incompatible client %{1}.%{2}", deskflow::string::sprintf("%d", m_major).c_str(),
@@ -68,17 +68,17 @@ String XIncompatibleClient::getWhat() const throw()
 // XDuplicateClient
 //
 
-XDuplicateClient::XDuplicateClient(const String &name) : m_name(name)
+XDuplicateClient::XDuplicateClient(const std::string &name) : m_name(name)
 {
   // do nothing
 }
 
-const String &XDuplicateClient::getName() const throw()
+const std::string &XDuplicateClient::getName() const throw()
 {
   return m_name;
 }
 
-String XDuplicateClient::getWhat() const throw()
+std::string XDuplicateClient::getWhat() const throw()
 {
   return format("XDuplicateClient", "duplicate client %{1}", m_name.c_str());
 }
@@ -87,17 +87,17 @@ String XDuplicateClient::getWhat() const throw()
 // XUnknownClient
 //
 
-XUnknownClient::XUnknownClient(const String &name) : m_name(name)
+XUnknownClient::XUnknownClient(const std::string &name) : m_name(name)
 {
   // do nothing
 }
 
-const String &XUnknownClient::getName() const throw()
+const std::string &XUnknownClient::getName() const throw()
 {
   return m_name;
 }
 
-String XUnknownClient::getWhat() const throw()
+std::string XUnknownClient::getWhat() const throw()
 {
   return format("XUnknownClient", "unknown client %{1}", m_name.c_str());
 }
@@ -116,7 +116,7 @@ int XExitApp::getCode() const throw()
   return m_code;
 }
 
-String XExitApp::getWhat() const throw()
+std::string XExitApp::getWhat() const throw()
 {
   return format("XExitApp", "exiting with code %{1}", deskflow::string::sprintf("%d", m_code).c_str());
 }
diff --git a/src/lib/deskflow/XDeskflow.h b/src/lib/deskflow/XDeskflow.h
index 1b899da92..ae4263eb3 100644
--- a/src/lib/deskflow/XDeskflow.h
+++ b/src/lib/deskflow/XDeskflow.h
@@ -61,7 +61,7 @@ public:
   //@}
 
 protected:
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
   int m_major;
@@ -76,7 +76,7 @@ a client that is already connected.
 class XDuplicateClient : public XDeskflow
 {
 public:
-  XDuplicateClient(const String &name);
+  XDuplicateClient(const std::string &name);
   virtual ~XDuplicateClient() _NOEXCEPT
   {
   }
@@ -85,15 +85,15 @@ public:
   //@{
 
   //! Get client's name
-  virtual const String &getName() const throw();
+  virtual const std::string &getName() const throw();
 
   //@}
 
 protected:
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
-  String m_name;
+  std::string m_name;
 };
 
 //! Client not in map exception
@@ -104,7 +104,7 @@ unknown to the server.
 class XUnknownClient : public XDeskflow
 {
 public:
-  XUnknownClient(const String &name);
+  XUnknownClient(const std::string &name);
   virtual ~XUnknownClient() _NOEXCEPT
   {
   }
@@ -113,15 +113,15 @@ public:
   //@{
 
   //! Get the client's name
-  virtual const String &getName() const throw();
+  virtual const std::string &getName() const throw();
 
   //@}
 
 protected:
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
-  String m_name;
+  std::string m_name;
 };
 
 //! Generic exit eception
@@ -142,7 +142,7 @@ public:
   int getCode() const throw();
 
 protected:
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
   int m_code;
diff --git a/src/lib/deskflow/XScreen.cpp b/src/lib/deskflow/XScreen.cpp
index c7dc1899d..183c56ac7 100644
--- a/src/lib/deskflow/XScreen.cpp
+++ b/src/lib/deskflow/XScreen.cpp
@@ -22,7 +22,7 @@
 // XScreenOpenFailure
 //
 
-String XScreenOpenFailure::getWhat() const throw()
+std::string XScreenOpenFailure::getWhat() const throw()
 {
   return format("XScreenOpenFailure", "unable to open screen");
 }
@@ -31,7 +31,7 @@ String XScreenOpenFailure::getWhat() const throw()
 // XScreenXInputFailure
 //
 
-String XScreenXInputFailure::getWhat() const throw()
+std::string XScreenXInputFailure::getWhat() const throw()
 {
   return "";
 }
@@ -55,7 +55,7 @@ double XScreenUnavailable::getRetryTime() const
   return m_timeUntilRetry;
 }
 
-String XScreenUnavailable::getWhat() const throw()
+std::string XScreenUnavailable::getWhat() const throw()
 {
   return format("XScreenUnavailable", "unable to open screen");
 }
diff --git a/src/lib/deskflow/XScreen.h b/src/lib/deskflow/XScreen.h
index e36507546..6c694390e 100644
--- a/src/lib/deskflow/XScreen.h
+++ b/src/lib/deskflow/XScreen.h
@@ -62,7 +62,7 @@ public:
   //@}
 
 protected:
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
   double m_timeUntilRetry;
diff --git a/src/lib/deskflow/languages/LanguageManager.cpp b/src/lib/deskflow/languages/LanguageManager.cpp
index 50b4b3fb6..a2ec45512 100644
--- a/src/lib/deskflow/languages/LanguageManager.cpp
+++ b/src/lib/deskflow/languages/LanguageManager.cpp
@@ -21,9 +21,9 @@
 
 namespace {
 
-String vectorToString(const std::vector<String> &vector, const String &delimiter = "")
+std::string vectorToString(const std::vector<std::string> &vector, const std::string &delimiter = "")
 {
-  String string;
+  std::string string;
   for (const auto &item : vector) {
     if (&item != &vector[0]) {
       string += delimiter;
@@ -39,12 +39,12 @@ namespace deskflow {
 
 namespace languages {
 
-LanguageManager::LanguageManager(const std::vector<String> &localLanguages) : m_localLanguages(localLanguages)
+LanguageManager::LanguageManager(const std::vector<std::string> &localLanguages) : m_localLanguages(localLanguages)
 {
   LOG((CLOG_INFO "local languages: %s", vectorToString(m_localLanguages, ", ").c_str()));
 }
 
-void LanguageManager::setRemoteLanguages(const String &remoteLanguages)
+void LanguageManager::setRemoteLanguages(const std::string &remoteLanguages)
 {
   m_remoteLanguages.clear();
   if (!remoteLanguages.empty()) {
@@ -55,19 +55,19 @@ void LanguageManager::setRemoteLanguages(const String &remoteLanguages)
   LOG((CLOG_INFO "remote languages: %s", vectorToString(m_remoteLanguages, ", ").c_str()));
 }
 
-const std::vector<String> &LanguageManager::getRemoteLanguages() const
+const std::vector<std::string> &LanguageManager::getRemoteLanguages() const
 {
   return m_remoteLanguages;
 }
 
-const std::vector<String> &LanguageManager::getLocalLanguages() const
+const std::vector<std::string> &LanguageManager::getLocalLanguages() const
 {
   return m_localLanguages;
 }
 
-String LanguageManager::getMissedLanguages() const
+std::string LanguageManager::getMissedLanguages() const
 {
-  String missedLanguages;
+  std::string missedLanguages;
 
   for (const auto &language : m_remoteLanguages) {
     if (!isLanguageInstalled(language)) {
@@ -81,12 +81,12 @@ String LanguageManager::getMissedLanguages() const
   return missedLanguages;
 }
 
-String LanguageManager::getSerializedLocalLanguages() const
+std::string LanguageManager::getSerializedLocalLanguages() const
 {
   return vectorToString(m_localLanguages);
 }
 
-bool LanguageManager::isLanguageInstalled(const String &language) const
+bool LanguageManager::isLanguageInstalled(const std::string &language) const
 {
   bool isInstalled = true;
 
diff --git a/src/lib/deskflow/languages/LanguageManager.h b/src/lib/deskflow/languages/LanguageManager.h
index 832a41659..fa6348a58 100644
--- a/src/lib/deskflow/languages/LanguageManager.h
+++ b/src/lib/deskflow/languages/LanguageManager.h
@@ -16,7 +16,6 @@
  */
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/AppUtil.h"
 #include <vector>
 
@@ -26,49 +25,51 @@ namespace languages {
 
 class LanguageManager
 {
-  std::vector<String> m_remoteLanguages;
-  std::vector<String> m_localLanguages;
+  std::vector<std::string> m_remoteLanguages;
+  std::vector<std::string> m_localLanguages;
 
 public:
-  explicit LanguageManager(const std::vector<String> &localLanguages = AppUtil::instance().getKeyboardLayoutList());
+  explicit LanguageManager(
+      const std::vector<std::string> &localLanguages = AppUtil::instance().getKeyboardLayoutList()
+  );
 
   /**
    * @brief setRemoteLanguages sets remote languages
    * @param remoteLanguages is a string with sericalized languages
    */
-  void setRemoteLanguages(const String &remoteLanguages);
+  void setRemoteLanguages(const std::string &remoteLanguages);
 
   /**
    * @brief getRemoteLanguages getter for remote languages
    * @return vector of remote languages
    */
-  const std::vector<String> &getRemoteLanguages() const;
+  const std::vector<std::string> &getRemoteLanguages() const;
 
   /**
    * @brief getLocalLanguages getter for local languages
    * @return vector of local languages
    */
-  const std::vector<String> &getLocalLanguages() const;
+  const std::vector<std::string> &getLocalLanguages() const;
 
   /**
    * @brief getMissedLanguages getter for missed languages on local machine
    * @return difference between remote and local languages as a coma separated
    * string
    */
-  String getMissedLanguages() const;
+  std::string getMissedLanguages() const;
 
   /**
    * @brief getSerializedLocalLanguages getter for local serialized languages
    * @return serialized local languages as a string
    */
-  String getSerializedLocalLanguages() const;
+  std::string getSerializedLocalLanguages() const;
 
   /**
    * @brief isLanguageInstalled checks if language is installed
    * @param language which should be checked
    * @return true if the specified language is installed
    */
-  bool isLanguageInstalled(const String &language) const;
+  bool isLanguageInstalled(const std::string &language) const;
 };
 
 } // namespace languages
diff --git a/src/lib/deskflow/unix/AppUtilUnix.cpp b/src/lib/deskflow/unix/AppUtilUnix.cpp
index fac1b6ea8..87836cbe0 100644
--- a/src/lib/deskflow/unix/AppUtilUnix.cpp
+++ b/src/lib/deskflow/unix/AppUtilUnix.cpp
@@ -60,9 +60,9 @@ void AppUtilUnix::startNode()
   app().startNode();
 }
 
-std::vector<String> AppUtilUnix::getKeyboardLayoutList()
+std::vector<std::string> AppUtilUnix::getKeyboardLayoutList()
 {
-  std::vector<String> layoutLangCodes;
+  std::vector<std::string> layoutLangCodes;
 
 #if WINAPI_XWINDOWS
   layoutLangCodes = X11LayoutsParser::getX11LanguageList("/usr/share/X11/xkb/rules/evdev.xml");
@@ -97,9 +97,9 @@ std::vector<String> AppUtilUnix::getKeyboardLayoutList()
   return layoutLangCodes;
 }
 
-String AppUtilUnix::getCurrentLanguageCode()
+std::string AppUtilUnix::getCurrentLanguageCode()
 {
-  String result = "";
+  std::string result = "";
 #if WINAPI_XWINDOWS
 
   auto display = XOpenDisplay(nullptr);
@@ -165,7 +165,7 @@ String AppUtilUnix::getCurrentLanguageCode()
   return result;
 }
 
-void AppUtilUnix::showNotification(const String &title, const String &text) const
+void AppUtilUnix::showNotification(const std::string &title, const std::string &text) const
 {
 #if HAVE_LIBNOTIFY
   LOG((CLOG_INFO "showing notification, title=\"%s\", text=\"%s\"", title.c_str(), text.c_str()));
diff --git a/src/lib/deskflow/unix/AppUtilUnix.h b/src/lib/deskflow/unix/AppUtilUnix.h
index 07a32ad84..3e6204a71 100644
--- a/src/lib/deskflow/unix/AppUtilUnix.h
+++ b/src/lib/deskflow/unix/AppUtilUnix.h
@@ -32,7 +32,7 @@ public:
 
   int run(int argc, char **argv) override;
   void startNode() override;
-  std::vector<String> getKeyboardLayoutList() override;
-  String getCurrentLanguageCode() override;
-  void showNotification(const String &title, const String &text) const override;
+  std::vector<std::string> getKeyboardLayoutList() override;
+  std::string getCurrentLanguageCode() override;
+  void showNotification(const std::string &title, const std::string &text) const override;
 };
diff --git a/src/lib/deskflow/unix/ISO639Table.h b/src/lib/deskflow/unix/ISO639Table.h
index 34868c714..94736fc96 100644
--- a/src/lib/deskflow/unix/ISO639Table.h
+++ b/src/lib/deskflow/unix/ISO639Table.h
@@ -18,13 +18,13 @@
 
 #pragma once
 
-#include "base/String.h"
-
+#include <string>
+#include <vector>
 // copy from
 // https://www.loc.gov/standards/iso639-2/php/code_list.php
 // 10.06.2021
 // first param - ISO 639-2, second param - 639-1
-const std::vector<std::pair<String, String>> ISO_Table = {
+const std::vector<std::pair<std::string, std::string>> ISO_Table = {
     std::make_pair("aar", "aa"), std::make_pair("abk", "ab"), std::make_pair("afr", "af"), std::make_pair("aka", "ak"),
     std::make_pair("sqi", "sq"), std::make_pair("amh", "am"), std::make_pair("ara", "ar"), std::make_pair("arg", "an"),
     std::make_pair("hye", "hy"), std::make_pair("asm", "as"), std::make_pair("ava", "av"), std::make_pair("ave", "ae"),
diff --git a/src/lib/deskflow/unix/X11LayoutsParser.cpp b/src/lib/deskflow/unix/X11LayoutsParser.cpp
index dd2f49add..105aeeaac 100644
--- a/src/lib/deskflow/unix/X11LayoutsParser.cpp
+++ b/src/lib/deskflow/unix/X11LayoutsParser.cpp
@@ -28,11 +28,11 @@
 
 namespace {
 
-void splitLine(std::vector<String> &parts, const String &line, char delimiter)
+void splitLine(std::vector<std::string> &parts, const std::string &line, char delimiter)
 {
   std::stringstream stream(line);
   while (stream.good()) {
-    String part;
+    std::string part;
     getline(stream, part, delimiter);
     parts.push_back(part);
   }
@@ -64,7 +64,7 @@ bool X11LayoutsParser::readXMLConfigItemElem(const pugi::xml_node *root, std::ve
   return true;
 }
 
-std::vector<X11LayoutsParser::Lang> X11LayoutsParser::getAllLanguageData(const String &pathToEvdevFile)
+std::vector<X11LayoutsParser::Lang> X11LayoutsParser::getAllLanguageData(const std::string &pathToEvdevFile)
 {
   std::vector<Lang> allCodes;
   pugi::xml_document doc;
@@ -101,18 +101,18 @@ std::vector<X11LayoutsParser::Lang> X11LayoutsParser::getAllLanguageData(const S
   return allCodes;
 }
 
-void X11LayoutsParser::appendVectorUniq(const std::vector<String> &source, std::vector<String> &dst)
+void X11LayoutsParser::appendVectorUniq(const std::vector<std::string> &source, std::vector<std::string> &dst)
 {
   for (const auto &elem : source) {
-    if (std::find_if(dst.begin(), dst.end(), [elem](const String &s) { return s == elem; }) == dst.end()) {
+    if (std::find_if(dst.begin(), dst.end(), [elem](const std::string &s) { return s == elem; }) == dst.end()) {
       dst.push_back(elem);
     }
   }
 };
 
 void X11LayoutsParser::convertLayoutToISO639_2(
-    const String &pathToEvdevFile, bool needToReloadEvdev, const std::vector<String> &layoutNames,
-    const std::vector<String> &layoutVariantNames, std::vector<String> &iso639_2Codes
+    const std::string &pathToEvdevFile, bool needToReloadEvdev, const std::vector<std::string> &layoutNames,
+    const std::vector<std::string> &layoutVariantNames, std::vector<std::string> &iso639_2Codes
 )
 {
   if (layoutNames.size() != layoutVariantNames.size()) {
@@ -133,7 +133,7 @@ void X11LayoutsParser::convertLayoutToISO639_2(
       continue;
     }
 
-    const std::vector<String> *toCopy = nullptr;
+    const std::vector<std::string> *toCopy = nullptr;
     if (layoutVariantNames[i].empty()) {
       toCopy = &langIter->layoutBaseISO639_2;
     } else {
@@ -163,25 +163,26 @@ void X11LayoutsParser::convertLayoutToISO639_2(
   }
 }
 
-std::vector<String> X11LayoutsParser::getX11LanguageList(const String &pathToEvdevFile)
+std::vector<std::string> X11LayoutsParser::getX11LanguageList(const std::string &pathToEvdevFile)
 {
-  std::vector<String> layoutNames;
-  std::vector<String> layoutVariantNames;
+  std::vector<std::string> layoutNames;
+  std::vector<std::string> layoutVariantNames;
 
   deskflow::linux::DeskflowXkbKeyboard keyboard;
   splitLine(layoutNames, keyboard.getLayout(), ',');
   splitLine(layoutVariantNames, keyboard.getVariant(), ',');
 
-  std::vector<String> iso639_2Codes;
+  std::vector<std::string> iso639_2Codes;
   iso639_2Codes.reserve(layoutNames.size());
   convertLayoutToISO639_2(pathToEvdevFile, true, layoutNames, layoutVariantNames, iso639_2Codes);
   return convertISO639_2ToISO639_1(iso639_2Codes);
 }
 
-String
-X11LayoutsParser::convertLayotToISO(const String &pathToEvdevFile, const String &layoutLangCode, bool needToReloadFiles)
+std::string X11LayoutsParser::convertLayotToISO(
+    const std::string &pathToEvdevFile, const std::string &layoutLangCode, bool needToReloadFiles
+)
 {
-  std::vector<String> iso639_2Codes;
+  std::vector<std::string> iso639_2Codes;
   convertLayoutToISO639_2(pathToEvdevFile, needToReloadFiles, {layoutLangCode}, {""}, iso639_2Codes);
   if (iso639_2Codes.empty()) {
     LOG((CLOG_WARN "failed to convert layout lang code: \"%s\"", layoutLangCode.c_str()));
@@ -197,12 +198,12 @@ X11LayoutsParser::convertLayotToISO(const String &pathToEvdevFile, const String
   return *iso639_1Codes.begin();
 }
 
-std::vector<String> X11LayoutsParser::convertISO639_2ToISO639_1(const std::vector<String> &iso639_2Codes)
+std::vector<std::string> X11LayoutsParser::convertISO639_2ToISO639_1(const std::vector<std::string> &iso639_2Codes)
 {
-  std::vector<String> result;
+  std::vector<std::string> result;
   for (const auto &isoCode : iso639_2Codes) {
     const auto &tableIter =
-        std::find_if(ISO_Table.begin(), ISO_Table.end(), [&isoCode](const std::pair<String, String> &c) {
+        std::find_if(ISO_Table.begin(), ISO_Table.end(), [&isoCode](const std::pair<std::string, std::string> &c) {
           return c.first == isoCode;
         });
     if (tableIter == ISO_Table.end()) {
diff --git a/src/lib/deskflow/unix/X11LayoutsParser.h b/src/lib/deskflow/unix/X11LayoutsParser.h
index 01947c25a..41daf56cf 100644
--- a/src/lib/deskflow/unix/X11LayoutsParser.h
+++ b/src/lib/deskflow/unix/X11LayoutsParser.h
@@ -18,7 +18,9 @@
 
 #if WINAPI_XWINDOWS
 #pragma once
-#include "base/String.h"
+
+#include <string>
+#include <vector>
 
 namespace pugi {
 class xml_node;
@@ -27,30 +29,31 @@ class xml_node;
 class X11LayoutsParser
 {
 public:
-  static std::vector<String> getX11LanguageList(const String &pathToEvdevFile);
-  static String
-  convertLayotToISO(const String &pathToEvdevFile, const String &layoutLangCode, bool needToReloadFiles = false);
+  static std::vector<std::string> getX11LanguageList(const std::string &pathToEvdevFile);
+  static std::string convertLayotToISO(
+      const std::string &pathToEvdevFile, const std::string &layoutLangCode, bool needToReloadFiles = false
+  );
 
 private:
   struct Lang
   {
-    String name = "";
-    std::vector<String> layoutBaseISO639_2;
+    std::string name = "";
+    std::vector<std::string> layoutBaseISO639_2;
     std::vector<Lang> variants;
   };
 
   static bool readXMLConfigItemElem(const pugi::xml_node *root, std::vector<Lang> &langList);
 
-  static std::vector<Lang> getAllLanguageData(const String &pathToEvdevFile);
+  static std::vector<Lang> getAllLanguageData(const std::string &pathToEvdevFile);
 
-  static void appendVectorUniq(const std::vector<String> &source, std::vector<String> &dst);
+  static void appendVectorUniq(const std::vector<std::string> &source, std::vector<std::string> &dst);
 
   static void convertLayoutToISO639_2(
-      const String &pathToEvdevFile, bool needToReloadEvdev, const std::vector<String> &layoutNames,
-      const std::vector<String> &layoutVariantNames, std::vector<String> &iso639_2Codes
+      const std::string &pathToEvdevFile, bool needToReloadEvdev, const std::vector<std::string> &layoutNames,
+      const std::vector<std::string> &layoutVariantNames, std::vector<std::string> &iso639_2Codes
   );
 
-  static std::vector<String> convertISO639_2ToISO639_1(const std::vector<String> &iso639_2Codes);
+  static std::vector<std::string> convertISO639_2ToISO639_1(const std::vector<std::string> &iso639_2Codes);
 };
 
 #endif // WINAPI_XWINDOWS
diff --git a/src/lib/deskflow/win32/AppUtilWindows.cpp b/src/lib/deskflow/win32/AppUtilWindows.cpp
index 92c43760c..161fa70ed 100644
--- a/src/lib/deskflow/win32/AppUtilWindows.cpp
+++ b/src/lib/deskflow/win32/AppUtilWindows.cpp
@@ -169,16 +169,16 @@ void AppUtilWindows::startNode()
   app().startNode();
 }
 
-std::vector<String> AppUtilWindows::getKeyboardLayoutList()
+std::vector<std::string> AppUtilWindows::getKeyboardLayoutList()
 {
-  std::vector<String> layoutLangCodes;
+  std::vector<std::string> layoutLangCodes;
   {
     auto uLayouts = GetKeyboardLayoutList(0, NULL);
     auto lpList = (HKL *)LocalAlloc(LPTR, (uLayouts * sizeof(HKL)));
     uLayouts = GetKeyboardLayoutList(uLayouts, lpList);
 
     for (int i = 0; i < uLayouts; ++i) {
-      String code("", 2);
+      std::string code("", 2);
       GetLocaleInfoA(
           MAKELCID(((ULONG_PTR)lpList[i] & 0xffffffff), SORT_DEFAULT), LOCALE_SISO639LANGNAME, &code[0],
           static_cast<int>(code.size())
@@ -193,9 +193,9 @@ std::vector<String> AppUtilWindows::getKeyboardLayoutList()
   return layoutLangCodes;
 }
 
-String AppUtilWindows::getCurrentLanguageCode()
+std::string AppUtilWindows::getCurrentLanguageCode()
 {
-  String code("", 2);
+  std::string code("", 2);
 
   auto hklLayout = getCurrentKeyboardLayout();
   if (hklLayout) {
@@ -243,7 +243,7 @@ public:
 };
 #endif
 
-void AppUtilWindows::showNotification(const String &title, const String &text) const
+void AppUtilWindows::showNotification(const std::string &title, const std::string &text) const
 {
 #if HAVE_WINTOAST
   LOG((CLOG_INFO "showing notification, title=\"%s\", text=\"%s\"", title.c_str(), text.c_str()));
diff --git a/src/lib/deskflow/win32/AppUtilWindows.h b/src/lib/deskflow/win32/AppUtilWindows.h
index 46230beca..662d33cb3 100644
--- a/src/lib/deskflow/win32/AppUtilWindows.h
+++ b/src/lib/deskflow/win32/AppUtilWindows.h
@@ -48,10 +48,10 @@ public:
   void exitApp(int code) override;
   void beforeAppExit() override;
   void startNode() override;
-  std::vector<String> getKeyboardLayoutList() override;
-  String getCurrentLanguageCode() override;
+  std::vector<std::string> getKeyboardLayoutList() override;
+  std::string getCurrentLanguageCode() override;
   HKL getCurrentKeyboardLayout() const;
-  void showNotification(const String &title, const String &text) const override;
+  void showNotification(const std::string &title, const std::string &text) const override;
 
 private:
   AppExitMode m_exitMode;
diff --git a/src/lib/io/XIO.cpp b/src/lib/io/XIO.cpp
index f09541435..0eb563aa3 100644
--- a/src/lib/io/XIO.cpp
+++ b/src/lib/io/XIO.cpp
@@ -22,7 +22,7 @@
 // XIOClosed
 //
 
-String XIOClosed::getWhat() const throw()
+std::string XIOClosed::getWhat() const throw()
 {
   return format("XIOClosed", "already closed");
 }
@@ -31,7 +31,7 @@ String XIOClosed::getWhat() const throw()
 // XIOEndOfStream
 //
 
-String XIOEndOfStream::getWhat() const throw()
+std::string XIOEndOfStream::getWhat() const throw()
 {
   return format("XIOEndOfStream", "reached end of stream");
 }
@@ -40,7 +40,7 @@ String XIOEndOfStream::getWhat() const throw()
 // XIOWouldBlock
 //
 
-String XIOWouldBlock::getWhat() const throw()
+std::string XIOWouldBlock::getWhat() const throw()
 {
   return format("XIOWouldBlock", "stream operation would block");
 }
diff --git a/src/lib/ipc/IpcClientProxy.cpp b/src/lib/ipc/IpcClientProxy.cpp
index 8f27ccbdd..7060f097e 100644
--- a/src/lib/ipc/IpcClientProxy.cpp
+++ b/src/lib/ipc/IpcClientProxy.cpp
@@ -130,7 +130,7 @@ void IpcClientProxy::send(const IpcMessage &message)
   switch (message.type()) {
   case IpcMessageType::LogLine: {
     const IpcLogLineMessage &llm = static_cast<const IpcLogLineMessage &>(message);
-    const String logLine = llm.logLine();
+    const std::string logLine = llm.logLine();
     ProtocolUtil::writef(&m_stream, kIpcMsgLogLine, &logLine);
     break;
   }
@@ -162,7 +162,7 @@ IpcHelloMessage *IpcClientProxy::parseHello()
 
 IpcCommandMessage *IpcClientProxy::parseCommand()
 {
-  String command;
+  std::string command;
   UInt8 elevate;
   ProtocolUtil::readf(&m_stream, kIpcMsgCommand + 4, &command, &elevate);
 
@@ -172,8 +172,8 @@ IpcCommandMessage *IpcClientProxy::parseCommand()
 
 IpcSettingMessage *IpcClientProxy::parseSetting() const
 {
-  String name;
-  String value;
+  std::string name;
+  std::string value;
 
   ProtocolUtil::readf(&m_stream, kIpcMsgSetting + 4, &name, &value);
 
diff --git a/src/lib/ipc/IpcLogOutputter.cpp b/src/lib/ipc/IpcLogOutputter.cpp
index 401fa3aa5..30be28327 100644
--- a/src/lib/ipc/IpcLogOutputter.cpp
+++ b/src/lib/ipc/IpcLogOutputter.cpp
@@ -108,7 +108,7 @@ bool IpcLogOutputter::write(ELevel, const char *text)
   return true;
 }
 
-void IpcLogOutputter::appendBuffer(const String &text)
+void IpcLogOutputter::appendBuffer(const std::string &text)
 {
   ArchMutexLock lock(m_bufferMutex);
 
@@ -166,7 +166,7 @@ void IpcLogOutputter::notifyBuffer()
   ARCH->broadcastCondVar(m_notifyCond);
 }
 
-String IpcLogOutputter::getChunk(size_t count)
+std::string IpcLogOutputter::getChunk(size_t count)
 {
   ArchMutexLock lock(m_bufferMutex);
 
@@ -174,7 +174,7 @@ String IpcLogOutputter::getChunk(size_t count)
     count = m_buffer.size();
   }
 
-  String chunk;
+  std::string chunk;
   for (size_t i = 0; i < count; i++) {
     chunk.append(m_buffer.front());
     chunk.append("\n");
diff --git a/src/lib/ipc/IpcLogOutputter.h b/src/lib/ipc/IpcLogOutputter.h
index 8879cb182..fac8db285 100644
--- a/src/lib/ipc/IpcLogOutputter.h
+++ b/src/lib/ipc/IpcLogOutputter.h
@@ -93,12 +93,12 @@ public:
 private:
   void init();
   void bufferThread(void *);
-  String getChunk(size_t count);
-  void appendBuffer(const String &text);
+  std::string getChunk(size_t count);
+  void appendBuffer(const std::string &text);
   bool isRunning();
 
 private:
-  using Buffer = std::deque<String>;
+  using Buffer = std::deque<std::string>;
 
   IpcServer &m_ipcServer;
   Buffer m_buffer;
diff --git a/src/lib/ipc/IpcMessage.cpp b/src/lib/ipc/IpcMessage.cpp
index 474af9532..6949e6f02 100644
--- a/src/lib/ipc/IpcMessage.cpp
+++ b/src/lib/ipc/IpcMessage.cpp
@@ -35,11 +35,13 @@ IpcShutdownMessage::IpcShutdownMessage() : IpcMessage(IpcMessageType::Shutdown)
 {
 }
 
-IpcLogLineMessage::IpcLogLineMessage(const String &logLine) : IpcMessage(IpcMessageType::LogLine), m_logLine(logLine)
+IpcLogLineMessage::IpcLogLineMessage(const std::string &logLine)
+    : IpcMessage(IpcMessageType::LogLine),
+      m_logLine(logLine)
 {
 }
 
-IpcCommandMessage::IpcCommandMessage(const String &command, bool elevate)
+IpcCommandMessage::IpcCommandMessage(const std::string &command, bool elevate)
     : IpcMessage(IpcMessageType::Command),
       m_command(command),
       m_elevate(elevate)
diff --git a/src/lib/ipc/IpcMessage.h b/src/lib/ipc/IpcMessage.h
index 5d043ef49..74be7422e 100644
--- a/src/lib/ipc/IpcMessage.h
+++ b/src/lib/ipc/IpcMessage.h
@@ -18,9 +18,10 @@
 #pragma once
 
 #include "base/Event.h"
-#include "base/String.h"
 #include "common/ipc.h"
 
+#include <string>
+
 class IpcMessage : public EventData
 {
 public:
@@ -72,27 +73,27 @@ public:
 class IpcLogLineMessage : public IpcMessage
 {
 public:
-  explicit IpcLogLineMessage(const String &logLine);
+  explicit IpcLogLineMessage(const std::string &logLine);
   ~IpcLogLineMessage() override = default;
 
   //! Gets the log line.
-  String logLine() const
+  std::string logLine() const
   {
     return m_logLine;
   }
 
 private:
-  String m_logLine;
+  std::string m_logLine;
 };
 
 class IpcCommandMessage : public IpcMessage
 {
 public:
-  explicit IpcCommandMessage(const String &command, bool elevate);
+  explicit IpcCommandMessage(const std::string &command, bool elevate);
   ~IpcCommandMessage() override = default;
 
   //! Gets the command.
-  String command() const
+  std::string command() const
   {
     return m_command;
   }
@@ -104,6 +105,6 @@ public:
   }
 
 private:
-  String m_command;
+  std::string m_command;
   bool m_elevate;
 };
diff --git a/src/lib/ipc/IpcServerProxy.cpp b/src/lib/ipc/IpcServerProxy.cpp
index ab27814f1..eaa8edf77 100644
--- a/src/lib/ipc/IpcServerProxy.cpp
+++ b/src/lib/ipc/IpcServerProxy.cpp
@@ -86,7 +86,7 @@ void IpcServerProxy::send(const IpcMessage &message)
 
   case IpcMessageType::Command: {
     const IpcCommandMessage &cm = static_cast<const IpcCommandMessage &>(message);
-    const String command = cm.command();
+    const std::string command = cm.command();
     ProtocolUtil::writef(&m_stream, kIpcMsgCommand, &command);
     break;
   }
@@ -99,7 +99,7 @@ void IpcServerProxy::send(const IpcMessage &message)
 
 IpcLogLineMessage *IpcServerProxy::parseLogLine()
 {
-  String logLine;
+  std::string logLine;
   ProtocolUtil::readf(&m_stream, kIpcMsgLogLine + 4, &logLine);
 
   // must be deleted by event handler.
diff --git a/src/lib/mt/XMT.cpp b/src/lib/mt/XMT.cpp
index 876031ba2..e6c7b44ac 100644
--- a/src/lib/mt/XMT.cpp
+++ b/src/lib/mt/XMT.cpp
@@ -22,7 +22,7 @@
 // XMTThreadUnavailable
 //
 
-String XMTThreadUnavailable::getWhat() const throw()
+std::string XMTThreadUnavailable::getWhat() const throw()
 {
   return format("XMTThreadUnavailable", "cannot create thread");
 }
diff --git a/src/lib/net/IDataSocket.h b/src/lib/net/IDataSocket.h
index 5c7b79df3..ce8ded330 100644
--- a/src/lib/net/IDataSocket.h
+++ b/src/lib/net/IDataSocket.h
@@ -19,7 +19,6 @@
 #pragma once
 
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "io/IStream.h"
 #include "net/ISocket.h"
 
@@ -37,7 +36,7 @@ public:
     ConnectionFailedInfo(const char *what) : m_what(what)
     {
     }
-    String m_what;
+    std::string m_what;
   };
 
   IDataSocket(IEventQueue *events)
diff --git a/src/lib/net/InverseSockets/SecureServerSocket.cpp b/src/lib/net/InverseSockets/SecureServerSocket.cpp
index 6f1c6682f..89bce0110 100644
--- a/src/lib/net/InverseSockets/SecureServerSocket.cpp
+++ b/src/lib/net/InverseSockets/SecureServerSocket.cpp
@@ -18,6 +18,7 @@
 #include "SecureServerSocket.h"
 
 #include <arch/XArch.h>
+#include <base/String.h>
 #include <common/constants.h>
 #include <deskflow/ArgParser.h>
 #include <deskflow/ArgsBase.h>
diff --git a/src/lib/net/InverseSockets/SslApi.cpp b/src/lib/net/InverseSockets/SslApi.cpp
index 3a8d51dc5..2512c924c 100644
--- a/src/lib/net/InverseSockets/SslApi.cpp
+++ b/src/lib/net/InverseSockets/SslApi.cpp
@@ -6,6 +6,7 @@
 
 #include <base/Log.h>
 #include <base/Path.h>
+#include <base/String.h>
 #include <openssl/err.h>
 
 namespace deskflow {
diff --git a/src/lib/net/NetworkAddress.cpp b/src/lib/net/NetworkAddress.cpp
index e747d72d0..98fa2f8d2 100644
--- a/src/lib/net/NetworkAddress.cpp
+++ b/src/lib/net/NetworkAddress.cpp
@@ -43,7 +43,7 @@ NetworkAddress::NetworkAddress(const NetworkAddress &addr) : m_hostname(addr.m_h
   *this = addr;
 }
 
-NetworkAddress::NetworkAddress(const String &hostname, int port) : m_hostname(hostname), m_port(port)
+NetworkAddress::NetworkAddress(const std::string &hostname, int port) : m_hostname(hostname), m_port(port)
 {
   // detect internet protocol version with colom count
   auto isColomPredicate = [](char c) { return c == ':'; };
@@ -64,11 +64,11 @@ NetworkAddress::NetworkAddress(const String &hostname, int port) : m_hostname(ho
     // ipv6 part
     if (m_hostname[0] == '[') {
       // ipv6 with port part
-      String portDelimeter = "]:";
+      std::string portDelimeter = "]:";
       auto hostIt = m_hostname.find(portDelimeter);
 
       // bad syntax of ipv6 with port
-      if (hostIt == String::npos) {
+      if (hostIt == std::string::npos) {
         throw XSocketAddress(XSocketAddress::kUnknown, m_hostname, m_port);
       }
 
@@ -89,7 +89,7 @@ NetworkAddress::NetworkAddress(const String &hostname, int port) : m_hostname(ho
     }
 
     // ensure that ipv6 link-local adress ended with scope id
-    if (m_hostname.rfind("fe80:", 0) == 0 && m_hostname.find('%') == String::npos) {
+    if (m_hostname.rfind("fe80:", 0) == 0 && m_hostname.find('%') == std::string::npos) {
       throw XSocketAddress(XSocketAddress::kUnknown, m_hostname, m_port);
     }
   }
@@ -208,7 +208,7 @@ int NetworkAddress::getPort() const
   return m_port;
 }
 
-String NetworkAddress::getHostname() const
+std::string NetworkAddress::getHostname() const
 {
   return m_hostname;
 }
diff --git a/src/lib/net/NetworkAddress.h b/src/lib/net/NetworkAddress.h
index 3cd7b6dc5..bc72edb1e 100644
--- a/src/lib/net/NetworkAddress.h
+++ b/src/lib/net/NetworkAddress.h
@@ -20,7 +20,6 @@
 
 #include "arch/IArchNetwork.h"
 #include "base/EventTypes.h"
-#include "base/String.h"
 
 //! Network address type
 /*!
@@ -50,7 +49,7 @@ public:
   is thrown with an error of \c XSocketAddress::kBadPort.  The hostname
   is not resolved by the c'tor;  use \c resolve to do that.
   */
-  NetworkAddress(const String &hostname, int port = 0);
+  NetworkAddress(const std::string &hostname, int port = 0);
 
   NetworkAddress(const NetworkAddress &);
 
@@ -112,7 +111,7 @@ public:
   /*!
   Returns the hostname passed to the c'tor sans any port suffix.
   */
-  String getHostname() const;
+  std::string getHostname() const;
 
   //@}
 
@@ -121,6 +120,6 @@ private:
 
 private:
   ArchNetAddress m_address = nullptr;
-  String m_hostname;
+  std::string m_hostname;
   int m_port = 0;
 };
diff --git a/src/lib/net/SecureListenSocket.cpp b/src/lib/net/SecureListenSocket.cpp
index ca3733cab..32d471b42 100644
--- a/src/lib/net/SecureListenSocket.cpp
+++ b/src/lib/net/SecureListenSocket.cpp
@@ -19,6 +19,7 @@
 
 #include "SecureSocket.h"
 #include "arch/XArch.h"
+#include "base/String.h"
 #include "common/constants.h"
 #include "deskflow/ArgParser.h"
 #include "deskflow/ArgsBase.h"
@@ -53,7 +54,7 @@ IDataSocket *SecureListenSocket::accept()
     }
 
     // default location of the TLS cert file in users dir
-    String certificateFilename = deskflow::string::sprintf(
+    std::string certificateFilename = deskflow::string::sprintf(
         "%s/%s/%s.%s", ARCH->getProfileDirectory().c_str(), s_certificateDir, kAppId, s_certificateFileExt
     );
 
diff --git a/src/lib/net/SecureSocket.cpp b/src/lib/net/SecureSocket.cpp
index dc97bed37..44cb14776 100644
--- a/src/lib/net/SecureSocket.cpp
+++ b/src/lib/net/SecureSocket.cpp
@@ -20,6 +20,7 @@
 #include "arch/XArch.h"
 #include "base/Log.h"
 #include "base/Path.h"
+#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "mt/Lock.h"
 #include "net/TCPSocket.h"
@@ -303,7 +304,7 @@ void SecureSocket::initSsl(bool server)
   initContext(server);
 }
 
-bool SecureSocket::loadCertificates(String &filename)
+bool SecureSocket::loadCertificates(std::string &filename)
 {
   std::lock_guard<std::mutex> ssl_lock{ssl_mutex_};
 
@@ -316,7 +317,7 @@ bool SecureSocket::loadCertificates(String &filename)
     file.close();
 
     if (!exist) {
-      String errorMsg("tls certificate doesn't exist: ");
+      std::string errorMsg("tls certificate doesn't exist: ");
       errorMsg.append(filename);
       SslLogger::logError(errorMsg.c_str());
       return false;
@@ -620,7 +621,7 @@ void SecureSocket::disconnect()
   sendEvent(getEvents()->forIStream().inputShutdown());
 }
 
-void SecureSocket::formatFingerprint(String &fingerprint, bool hex, bool separator)
+void SecureSocket::formatFingerprint(std::string &fingerprint, bool hex, bool separator)
 {
   if (hex) {
     // to hexidecimal
@@ -655,17 +656,17 @@ bool SecureSocket::verifyCertFingerprint()
   }
 
   // format fingerprint into hexdecimal format with colon separator
-  String fingerprint(static_cast<char *>(static_cast<void *>(tempFingerprint)), tempFingerprintLen);
+  std::string fingerprint(static_cast<char *>(static_cast<void *>(tempFingerprint)), tempFingerprintLen);
   formatFingerprint(fingerprint);
   LOG((CLOG_NOTE "server fingerprint: %s", fingerprint.c_str()));
 
-  String trustedServersFilename;
+  std::string trustedServersFilename;
   trustedServersFilename = deskflow::string::sprintf(
       "%s/%s/%s", ARCH->getProfileDirectory().c_str(), kFingerprintDirName, kFingerprintTrustedServersFilename
   );
 
   // check if this fingerprint exist
-  String fileLine;
+  std::string fileLine;
   std::ifstream file;
   file.open(deskflow::filesystem::path(trustedServersFilename));
 
diff --git a/src/lib/net/SecureSocket.h b/src/lib/net/SecureSocket.h
index bc3c00065..305d3b40f 100644
--- a/src/lib/net/SecureSocket.h
+++ b/src/lib/net/SecureSocket.h
@@ -66,7 +66,7 @@ public:
   EJobResult doRead() override;
   EJobResult doWrite() override;
   void initSsl(bool server);
-  bool loadCertificates(String &CertFile);
+  bool loadCertificates(std::string &CertFile);
 
 private:
   // SSL
@@ -78,7 +78,7 @@ private:
   bool showCertificate() const;
   void checkResult(int n, int &retry);
   void disconnect();
-  void formatFingerprint(String &fingerprint, bool hex = true, bool separator = true);
+  void formatFingerprint(std::string &fingerprint, bool hex = true, bool separator = true);
   bool verifyCertFingerprint();
 
   ISocketMultiplexerJob *serviceConnect(ISocketMultiplexerJob *, bool, bool, bool);
diff --git a/src/lib/net/XSocket.cpp b/src/lib/net/XSocket.cpp
index 61039810b..f60792827 100644
--- a/src/lib/net/XSocket.cpp
+++ b/src/lib/net/XSocket.cpp
@@ -23,9 +23,9 @@
 // XSocketAddress
 //
 
-XSocketAddress::XSocketAddress(EError error, const String &hostname, int port) _NOEXCEPT : m_error(error),
-                                                                                           m_hostname(hostname),
-                                                                                           m_port(port)
+XSocketAddress::XSocketAddress(EError error, const std::string &hostname, int port) _NOEXCEPT : m_error(error),
+                                                                                                m_hostname(hostname),
+                                                                                                m_port(port)
 {
   // do nothing
 }
@@ -35,7 +35,7 @@ XSocketAddress::EError XSocketAddress::getError() const throw()
   return m_error;
 }
 
-String XSocketAddress::getHostname() const throw()
+std::string XSocketAddress::getHostname() const throw()
 {
   return m_hostname;
 }
@@ -45,7 +45,7 @@ int XSocketAddress::getPort() const throw()
   return m_port;
 }
 
-String XSocketAddress::getWhat() const throw()
+std::string XSocketAddress::getWhat() const throw()
 {
   static const char *s_errorID[] = {
       "XSocketAddressUnknown", "XSocketAddressNotFound", "XSocketAddressNoAddress", "XSocketAddressUnsupported",
@@ -65,7 +65,7 @@ String XSocketAddress::getWhat() const throw()
 // XSocketIOClose
 //
 
-String XSocketIOClose::getWhat() const throw()
+std::string XSocketIOClose::getWhat() const throw()
 {
   return format("XSocketIOClose", "close: %{1}", what());
 }
@@ -74,7 +74,7 @@ String XSocketIOClose::getWhat() const throw()
 // XSocketBind
 //
 
-String XSocketBind::getWhat() const throw()
+std::string XSocketBind::getWhat() const throw()
 {
   return format("XSocketBind", "cannot bind address: %{1}", what());
 }
@@ -83,7 +83,7 @@ String XSocketBind::getWhat() const throw()
 // XSocketConnect
 //
 
-String XSocketConnect::getWhat() const throw()
+std::string XSocketConnect::getWhat() const throw()
 {
   return format("XSocketConnect", "cannot connect socket: %{1}", what());
 }
@@ -92,7 +92,7 @@ String XSocketConnect::getWhat() const throw()
 // XSocketCreate
 //
 
-String XSocketCreate::getWhat() const throw()
+std::string XSocketCreate::getWhat() const throw()
 {
   return format("XSocketCreate", "cannot create socket: %{1}", what());
 }
diff --git a/src/lib/net/XSocket.h b/src/lib/net/XSocket.h
index f678de6e8..820fcb3bb 100644
--- a/src/lib/net/XSocket.h
+++ b/src/lib/net/XSocket.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "base/XBase.h"
 #include "common/basic_types.h"
 #include "io/XIO.h"
@@ -43,7 +42,7 @@ public:
     kBadPort      //!< The port is invalid
   };
 
-  XSocketAddress(EError, const String &hostname, int port) _NOEXCEPT;
+  XSocketAddress(EError, const std::string &hostname, int port) _NOEXCEPT;
   virtual ~XSocketAddress() _NOEXCEPT
   {
   }
@@ -54,7 +53,7 @@ public:
   //! Get the error code
   EError getError() const throw();
   //! Get the hostname
-  String getHostname() const throw();
+  std::string getHostname() const throw();
   //! Get the port
   int getPort() const throw();
 
@@ -62,11 +61,11 @@ public:
 
 protected:
   // XBase overrides
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
   EError m_error;
-  String m_hostname;
+  std::string m_hostname;
   int m_port;
 };
 
diff --git a/src/lib/platform/EiScreen.cpp b/src/lib/platform/EiScreen.cpp
index 841f69bab..4de10376e 100644
--- a/src/lib/platform/EiScreen.cpp
+++ b/src/lib/platform/EiScreen.cpp
@@ -846,7 +846,7 @@ IKeyState *EiScreen::getKeyState() const
   return key_state_;
 }
 
-String EiScreen::getSecureInputApp() const
+std::string EiScreen::getSecureInputApp() const
 {
   throw std::runtime_error("get security input app not implemented");
 }
diff --git a/src/lib/platform/EiScreen.h b/src/lib/platform/EiScreen.h
index 9edec8d80..9637f7246 100644
--- a/src/lib/platform/EiScreen.h
+++ b/src/lib/platform/EiScreen.h
@@ -90,7 +90,7 @@ protected:
   void handleSystemEvent(const Event &event, void *) override;
   void updateButtons() override;
   IKeyState *getKeyState() const override;
-  String getSecureInputApp() const override;
+  std::string getSecureInputApp() const override;
 
   void update_shape();
   void add_device(ei_device *device);
diff --git a/src/lib/platform/MSWindowsClipboard.cpp b/src/lib/platform/MSWindowsClipboard.cpp
index 4efe71a88..26ca0a7e7 100644
--- a/src/lib/platform/MSWindowsClipboard.cpp
+++ b/src/lib/platform/MSWindowsClipboard.cpp
@@ -94,7 +94,7 @@ bool MSWindowsClipboard::empty()
   return true;
 }
 
-void MSWindowsClipboard::add(EFormat format, const String &data)
+void MSWindowsClipboard::add(EFormat format, const std::string &data)
 {
   // exit early if there is no data to prevent spurious "failed to convert clipboard data" errors
   if (data.empty()) {
@@ -163,7 +163,7 @@ bool MSWindowsClipboard::has(EFormat format) const
   return false;
 }
 
-String MSWindowsClipboard::get(EFormat format) const
+std::string MSWindowsClipboard::get(EFormat format) const
 {
   // find the converter for the first clipboard format we can handle
   IMSWindowsClipboardConverter *converter = NULL;
@@ -179,7 +179,7 @@ String MSWindowsClipboard::get(EFormat format) const
   // if no converter then we don't recognize any formats
   if (converter == NULL) {
     LOG((CLOG_WARN "no converter for format %d", format));
-    return String();
+    return std::string();
   }
 
   // get a handle to the clipboard data
@@ -188,7 +188,7 @@ String MSWindowsClipboard::get(EFormat format) const
     // nb: can't cause this using integ tests; this is only caused when
     // the selected converter returns an invalid format -- which you
     // cannot cause using public functions.
-    return String();
+    return std::string();
   }
 
   // convert
diff --git a/src/lib/platform/MSWindowsClipboard.h b/src/lib/platform/MSWindowsClipboard.h
index 66f51eb0f..db080a5b0 100644
--- a/src/lib/platform/MSWindowsClipboard.h
+++ b/src/lib/platform/MSWindowsClipboard.h
@@ -56,12 +56,12 @@ public:
 
   // IClipboard overrides
   virtual bool empty();
-  virtual void add(EFormat, const String &data);
+  virtual void add(EFormat, const std::string &data);
   virtual bool open(Time) const;
   virtual void close() const;
   virtual Time getTime() const;
   virtual bool has(EFormat) const;
-  virtual String get(EFormat) const;
+  virtual std::string get(EFormat) const;
 
   void setFacade(IMSWindowsClipboardFacade &facade);
 
@@ -69,8 +69,8 @@ private:
   void clearConverters();
 
   UINT convertFormatToWin32(EFormat) const;
-  HANDLE convertTextToWin32(const String &data) const;
-  String convertTextFromWin32(HANDLE) const;
+  HANDLE convertTextToWin32(const std::string &data) const;
+  std::string convertTextFromWin32(HANDLE) const;
 
   static UINT getOwnershipFormat();
 
@@ -106,9 +106,9 @@ public:
   // the input data must be in the IClipboard format returned by
   // getFormat().  the return data will be in the win32 clipboard
   // format returned by getWin32Format(), allocated by GlobalAlloc().
-  virtual HANDLE fromIClipboard(const String &) const = 0;
+  virtual HANDLE fromIClipboard(const std::string &) const = 0;
 
   // convert from the win32 clipboard format to the IClipboard format
   // (i.e., the reverse of fromIClipboard()).
-  virtual String toIClipboard(HANDLE data) const = 0;
+  virtual std::string toIClipboard(HANDLE data) const = 0;
 };
diff --git a/src/lib/platform/MSWindowsClipboardAnyTextConverter.cpp b/src/lib/platform/MSWindowsClipboardAnyTextConverter.cpp
index 56c80d3f7..cf300b441 100644
--- a/src/lib/platform/MSWindowsClipboardAnyTextConverter.cpp
+++ b/src/lib/platform/MSWindowsClipboardAnyTextConverter.cpp
@@ -38,10 +38,10 @@ IClipboard::EFormat MSWindowsClipboardAnyTextConverter::getFormat() const
 }
 
 HANDLE
-MSWindowsClipboardAnyTextConverter::fromIClipboard(const String &data) const
+MSWindowsClipboardAnyTextConverter::fromIClipboard(const std::string &data) const
 {
   // convert linefeeds and then convert to desired encoding
-  String text = doFromIClipboard(convertLinefeedToWin32(data));
+  std::string text = doFromIClipboard(convertLinefeedToWin32(data));
   UInt32 size = (UInt32)text.size();
 
   // copy to memory handle
@@ -61,17 +61,17 @@ MSWindowsClipboardAnyTextConverter::fromIClipboard(const String &data) const
   return gData;
 }
 
-String MSWindowsClipboardAnyTextConverter::toIClipboard(HANDLE data) const
+std::string MSWindowsClipboardAnyTextConverter::toIClipboard(HANDLE data) const
 {
   // get datator
   const char *src = (const char *)GlobalLock(data);
   UInt32 srcSize = (UInt32)GlobalSize(data);
   if (src == NULL || srcSize <= 1) {
-    return String();
+    return std::string();
   }
 
   // convert text
-  String text = doToIClipboard(String(src, srcSize));
+  std::string text = doToIClipboard(std::string(src, srcSize));
 
   // release handle
   GlobalUnlock(data);
@@ -80,7 +80,7 @@ String MSWindowsClipboardAnyTextConverter::toIClipboard(HANDLE data) const
   return convertLinefeedToUnix(text);
 }
 
-String MSWindowsClipboardAnyTextConverter::convertLinefeedToWin32(const String &src) const
+std::string MSWindowsClipboardAnyTextConverter::convertLinefeedToWin32(const std::string &src) const
 {
   // note -- we assume src is a valid UTF-8 string
 
@@ -97,7 +97,7 @@ String MSWindowsClipboardAnyTextConverter::convertLinefeedToWin32(const String &
   }
 
   // allocate new string
-  String dst;
+  std::string dst;
   dst.reserve(src.size() + numNewlines);
 
   // copy string, converting newlines
@@ -112,7 +112,7 @@ String MSWindowsClipboardAnyTextConverter::convertLinefeedToWin32(const String &
   return dst;
 }
 
-String MSWindowsClipboardAnyTextConverter::convertLinefeedToUnix(const String &src) const
+std::string MSWindowsClipboardAnyTextConverter::convertLinefeedToUnix(const std::string &src) const
 {
   // count newlines in string
   UInt32 numNewlines = 0;
@@ -127,7 +127,7 @@ String MSWindowsClipboardAnyTextConverter::convertLinefeedToUnix(const String &s
   }
 
   // allocate new string
-  String dst;
+  std::string dst;
   dst.reserve(src.size());
 
   // copy string, converting newlines
diff --git a/src/lib/platform/MSWindowsClipboardAnyTextConverter.h b/src/lib/platform/MSWindowsClipboardAnyTextConverter.h
index 383a134e7..8a9cd8f97 100644
--- a/src/lib/platform/MSWindowsClipboardAnyTextConverter.h
+++ b/src/lib/platform/MSWindowsClipboardAnyTextConverter.h
@@ -30,8 +30,8 @@ public:
   // IMSWindowsClipboardConverter overrides
   virtual IClipboard::EFormat getFormat() const;
   virtual UINT getWin32Format() const = 0;
-  virtual HANDLE fromIClipboard(const String &) const;
-  virtual String toIClipboard(HANDLE) const;
+  virtual HANDLE fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(HANDLE) const;
 
 protected:
   //! Convert from IClipboard format
@@ -39,18 +39,18 @@ protected:
   Do UTF-8 conversion only.  Memory handle allocation and
   linefeed conversion is done by this class.  doFromIClipboard()
   must include the nul terminator in the returned string (not
-  including the String's nul terminator).
+  including the std::string's nul terminator).
   */
-  virtual String doFromIClipboard(const String &) const = 0;
+  virtual std::string doFromIClipboard(const std::string &) const = 0;
 
   //! Convert to IClipboard format
   /*!
   Do UTF-8 conversion only.  Memory handle allocation and
   linefeed conversion is done by this class.
   */
-  virtual String doToIClipboard(const String &) const = 0;
+  virtual std::string doToIClipboard(const std::string &) const = 0;
 
 private:
-  String convertLinefeedToWin32(const String &) const;
-  String convertLinefeedToUnix(const String &) const;
+  std::string convertLinefeedToWin32(const std::string &) const;
+  std::string convertLinefeedToUnix(const std::string &) const;
 };
diff --git a/src/lib/platform/MSWindowsClipboardBitmapConverter.cpp b/src/lib/platform/MSWindowsClipboardBitmapConverter.cpp
index c6477b211..331517472 100644
--- a/src/lib/platform/MSWindowsClipboardBitmapConverter.cpp
+++ b/src/lib/platform/MSWindowsClipboardBitmapConverter.cpp
@@ -45,7 +45,7 @@ UINT MSWindowsClipboardBitmapConverter::getWin32Format() const
 }
 
 HANDLE
-MSWindowsClipboardBitmapConverter::fromIClipboard(const String &data) const
+MSWindowsClipboardBitmapConverter::fromIClipboard(const std::string &data) const
 {
   // copy to memory handle
   HGLOBAL gData = GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE, data.size());
@@ -64,12 +64,12 @@ MSWindowsClipboardBitmapConverter::fromIClipboard(const String &data) const
   return gData;
 }
 
-String MSWindowsClipboardBitmapConverter::toIClipboard(HANDLE data) const
+std::string MSWindowsClipboardBitmapConverter::toIClipboard(HANDLE data) const
 {
   // get datator
   LPVOID src = GlobalLock(data);
   if (src == NULL) {
-    return String();
+    return std::string();
   }
   UInt32 srcSize = (UInt32)GlobalSize(data);
 
@@ -82,7 +82,7 @@ String MSWindowsClipboardBitmapConverter::toIClipboard(HANDLE data) const
   if (bitmap->bmiHeader.biPlanes == 1 && (bitmap->bmiHeader.biBitCount == 24 || bitmap->bmiHeader.biBitCount == 32) &&
       bitmap->bmiHeader.biCompression == BI_RGB) {
     // already in canonical form
-    String image(static_cast<char const *>(src), srcSize);
+    std::string image(static_cast<char const *>(src), srcSize);
     GlobalUnlock(data);
     return image;
   }
@@ -131,7 +131,7 @@ String MSWindowsClipboardBitmapConverter::toIClipboard(HANDLE data) const
   GdiFlush();
 
   // extract data
-  String image((const char *)&info, info.biSize);
+  std::string image((const char *)&info, info.biSize);
   image.append((const char *)raw, 4 * w * h);
 
   // clean up GDI
diff --git a/src/lib/platform/MSWindowsClipboardBitmapConverter.h b/src/lib/platform/MSWindowsClipboardBitmapConverter.h
index 3ef05cc28..feea47088 100644
--- a/src/lib/platform/MSWindowsClipboardBitmapConverter.h
+++ b/src/lib/platform/MSWindowsClipboardBitmapConverter.h
@@ -30,6 +30,6 @@ public:
   // IMSWindowsClipboardConverter overrides
   virtual IClipboard::EFormat getFormat() const;
   virtual UINT getWin32Format() const;
-  virtual HANDLE fromIClipboard(const String &) const;
-  virtual String toIClipboard(HANDLE) const;
+  virtual HANDLE fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(HANDLE) const;
 };
diff --git a/src/lib/platform/MSWindowsClipboardHTMLConverter.cpp b/src/lib/platform/MSWindowsClipboardHTMLConverter.cpp
index 060e2f9aa..9040e88ed 100644
--- a/src/lib/platform/MSWindowsClipboardHTMLConverter.cpp
+++ b/src/lib/platform/MSWindowsClipboardHTMLConverter.cpp
@@ -18,7 +18,7 @@
 
 #include "platform/MSWindowsClipboardHTMLConverter.h"
 
-#include "base/String.h"
+#include <base/String.h>
 
 //
 // MSWindowsClipboardHTMLConverter
@@ -44,14 +44,14 @@ UINT MSWindowsClipboardHTMLConverter::getWin32Format() const
   return m_format;
 }
 
-String MSWindowsClipboardHTMLConverter::doFromIClipboard(const String &data) const
+std::string MSWindowsClipboardHTMLConverter::doFromIClipboard(const std::string &data) const
 {
   // prepare to CF_HTML format prefix and suffix
-  String prefix("Version:0.9\r\nStartHTML:0000000105\r\n"
-                "EndHTML:ZZZZZZZZZZ\r\n"
-                "StartFragment:XXXXXXXXXX\r\nEndFragment:YYYYYYYYYY\r\n"
-                "<!DOCTYPE><HTML><BODY><!--StartFragment-->");
-  String suffix("<!--EndFragment--></BODY></HTML>\r\n");
+  std::string prefix("Version:0.9\r\nStartHTML:0000000105\r\n"
+                     "EndHTML:ZZZZZZZZZZ\r\n"
+                     "StartFragment:XXXXXXXXXX\r\nEndFragment:YYYYYYYYYY\r\n"
+                     "<!DOCTYPE><HTML><BODY><!--StartFragment-->");
+  std::string suffix("<!--EndFragment--></BODY></HTML>\r\n");
 
   // Get byte offsets for header
   UInt32 StartFragment = (UInt32)prefix.size();
@@ -69,42 +69,44 @@ String MSWindowsClipboardHTMLConverter::doFromIClipboard(const String &data) con
   return prefix;
 }
 
-String MSWindowsClipboardHTMLConverter::doToIClipboard(const String &data) const
+std::string MSWindowsClipboardHTMLConverter::doToIClipboard(const std::string &data) const
 {
   // get fragment start/end args
-  String startArg = findArg(data, "StartFragment");
-  String endArg = findArg(data, "EndFragment");
+  std::string startArg = findArg(data, "StartFragment");
+  std::string endArg = findArg(data, "EndFragment");
   if (startArg.empty() || endArg.empty()) {
-    return String();
+    return std::string();
   }
 
   // convert args to integers
   SInt32 start = (SInt32)atoi(startArg.c_str());
   SInt32 end = (SInt32)atoi(endArg.c_str());
   if (start <= 0 || end <= 0 || start >= end) {
-    return String();
+    return std::string();
   }
 
   // extract the fragment
   return data.substr(start, end - start);
 }
 
-String MSWindowsClipboardHTMLConverter::findArg(const String &data, const String &name) const
+std::string MSWindowsClipboardHTMLConverter::findArg(const std::string &data, const std::string &name) const
 {
-  String::size_type i = data.find(name);
-  if (i == String::npos) {
-    return String();
+  std::string::size_type i = data.find(name);
+  if (i == std::string::npos) {
+    return std::string();
   }
+
   i = data.find_first_of(":\r\n", i);
-  if (i == String::npos || data[i] != ':') {
-    return String();
+  if (i == std::string::npos || data[i] != ':') {
+    return std::string();
   }
   i = data.find_first_of("0123456789\r\n", i + 1);
-  if (i == String::npos || data[i] == '\r' || data[i] == '\n') {
-    return String();
+  if (i == std::string::npos || data[i] == '\r' || data[i] == '\n') {
+    return std::string();
   }
-  String::size_type j = data.find_first_not_of("0123456789", i);
-  if (j == String::npos) {
+
+  std::string::size_type j = data.find_first_not_of("0123456789", i);
+  if (j == std::string::npos) {
     j = data.size();
   }
   return data.substr(i, j - i);
diff --git a/src/lib/platform/MSWindowsClipboardHTMLConverter.h b/src/lib/platform/MSWindowsClipboardHTMLConverter.h
index e978e4760..045798e73 100644
--- a/src/lib/platform/MSWindowsClipboardHTMLConverter.h
+++ b/src/lib/platform/MSWindowsClipboardHTMLConverter.h
@@ -33,11 +33,11 @@ public:
 
 protected:
   // MSWindowsClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 
 private:
-  String findArg(const String &data, const String &name) const;
+  std::string findArg(const std::string &data, const std::string &name) const;
 
 private:
   UINT m_format;
diff --git a/src/lib/platform/MSWindowsClipboardTextConverter.cpp b/src/lib/platform/MSWindowsClipboardTextConverter.cpp
index a678d00f8..9f541916a 100644
--- a/src/lib/platform/MSWindowsClipboardTextConverter.cpp
+++ b/src/lib/platform/MSWindowsClipboardTextConverter.cpp
@@ -39,18 +39,18 @@ UINT MSWindowsClipboardTextConverter::getWin32Format() const
   return CF_TEXT;
 }
 
-String MSWindowsClipboardTextConverter::doFromIClipboard(const String &data) const
+std::string MSWindowsClipboardTextConverter::doFromIClipboard(const std::string &data) const
 {
   // convert and add nul terminator
   return Unicode::UTF8ToText(data) += '\0';
 }
 
-String MSWindowsClipboardTextConverter::doToIClipboard(const String &data) const
+std::string MSWindowsClipboardTextConverter::doToIClipboard(const std::string &data) const
 {
   // convert and truncate at first nul terminator
-  String dst = Unicode::textToUTF8(data);
-  String::size_type n = dst.find('\0');
-  if (n != String::npos) {
+  std::string dst = Unicode::textToUTF8(data);
+  std::string::size_type n = dst.find('\0');
+  if (n != std::string::npos) {
     dst.erase(n);
   }
   return dst;
diff --git a/src/lib/platform/MSWindowsClipboardTextConverter.h b/src/lib/platform/MSWindowsClipboardTextConverter.h
index 5e42b3e5d..90b4fd2fa 100644
--- a/src/lib/platform/MSWindowsClipboardTextConverter.h
+++ b/src/lib/platform/MSWindowsClipboardTextConverter.h
@@ -32,6 +32,6 @@ public:
 
 protected:
   // MSWindowsClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 };
diff --git a/src/lib/platform/MSWindowsClipboardUTF16Converter.cpp b/src/lib/platform/MSWindowsClipboardUTF16Converter.cpp
index f521d84a0..e1284e126 100644
--- a/src/lib/platform/MSWindowsClipboardUTF16Converter.cpp
+++ b/src/lib/platform/MSWindowsClipboardUTF16Converter.cpp
@@ -39,18 +39,18 @@ UINT MSWindowsClipboardUTF16Converter::getWin32Format() const
   return CF_UNICODETEXT;
 }
 
-String MSWindowsClipboardUTF16Converter::doFromIClipboard(const String &data) const
+std::string MSWindowsClipboardUTF16Converter::doFromIClipboard(const std::string &data) const
 {
   // convert and add nul terminator
   return Unicode::UTF8ToUTF16(data).append(sizeof(wchar_t), 0);
 }
 
-String MSWindowsClipboardUTF16Converter::doToIClipboard(const String &data) const
+std::string MSWindowsClipboardUTF16Converter::doToIClipboard(const std::string &data) const
 {
   // convert and strip nul terminator
-  String dst = Unicode::UTF16ToUTF8(data);
-  String::size_type n = dst.find('\0');
-  if (n != String::npos) {
+  std::string dst = Unicode::UTF16ToUTF8(data);
+  std::string::size_type n = dst.find('\0');
+  if (n != std::string::npos) {
     dst.erase(n);
   }
   return dst;
diff --git a/src/lib/platform/MSWindowsClipboardUTF16Converter.h b/src/lib/platform/MSWindowsClipboardUTF16Converter.h
index 6eae650f9..6774dad99 100644
--- a/src/lib/platform/MSWindowsClipboardUTF16Converter.h
+++ b/src/lib/platform/MSWindowsClipboardUTF16Converter.h
@@ -32,6 +32,6 @@ public:
 
 protected:
   // MSWindowsClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 };
diff --git a/src/lib/platform/MSWindowsDesks.cpp b/src/lib/platform/MSWindowsDesks.cpp
index 08e4bd4c6..ea356dd49 100644
--- a/src/lib/platform/MSWindowsDesks.cpp
+++ b/src/lib/platform/MSWindowsDesks.cpp
@@ -726,7 +726,7 @@ void MSWindowsDesks::deskThread(void *vdesk)
   }
 }
 
-MSWindowsDesks::Desk *MSWindowsDesks::addDesk(const String &name, HDESK hdesk)
+MSWindowsDesks::Desk *MSWindowsDesks::addDesk(const std::string &name, HDESK hdesk)
 {
   Desk *desk = new Desk;
   desk->m_name = name;
@@ -757,7 +757,7 @@ void MSWindowsDesks::checkDesk()
   // get current desktop.  if we already know about it then return.
   Desk *desk;
   HDESK hdesk = openInputDesktop();
-  String name = getDesktopName(hdesk);
+  std::string name = getDesktopName(hdesk);
   Desks::const_iterator index = m_desks.find(name);
   if (index == m_desks.end()) {
     desk = addDesk(name, hdesk);
@@ -866,16 +866,16 @@ void MSWindowsDesks::closeDesktop(HDESK desk)
   }
 }
 
-String MSWindowsDesks::getDesktopName(HDESK desk)
+std::string MSWindowsDesks::getDesktopName(HDESK desk)
 {
   if (desk == NULL) {
-    return String();
+    return std::string();
   } else {
     DWORD size;
     GetUserObjectInformation(desk, UOI_NAME, NULL, 0, &size);
     TCHAR *name = (TCHAR *)alloca(size + sizeof(TCHAR));
     GetUserObjectInformation(desk, UOI_NAME, name, size, &size);
-    String result(name);
+    std::string result(name);
     return result;
   }
 }
diff --git a/src/lib/platform/MSWindowsDesks.h b/src/lib/platform/MSWindowsDesks.h
index 05efee5ba..ea706a579 100644
--- a/src/lib/platform/MSWindowsDesks.h
+++ b/src/lib/platform/MSWindowsDesks.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdmap.h"
 #include "deskflow/key_types.h"
 #include "deskflow/mouse_types.h"
@@ -27,6 +26,8 @@
 #include "mt/Mutex.h"
 #include "platform/dfwhook.h"
 
+#include <string>
+
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 
@@ -193,7 +194,7 @@ private:
   class Desk
   {
   public:
-    String m_name;
+    std::string m_name;
     Thread *m_thread;
     DWORD m_threadID;
     DWORD m_targetID;
@@ -202,7 +203,7 @@ private:
     HWND m_foregroundWindow;
     bool m_lowLevel;
   };
-  using Desks = std::map<String, Desk *>;
+  using Desks = std::map<std::string, Desk *>;
 
   // initialization and shutdown operations
   HCURSOR createBlankCursor() const;
@@ -220,7 +221,7 @@ private:
   void deskThread(void *vdesk);
 
   // desk switch checking and handling
-  Desk *addDesk(const String &name, HDESK hdesk);
+  Desk *addDesk(const std::string &name, HDESK hdesk);
   void removeDesks();
   void checkDesk();
   bool isDeskAccessible(const Desk *desk) const;
@@ -236,7 +237,7 @@ private:
   // desk API wrappers
   HDESK openInputDesktop();
   void closeDesktop(HDESK);
-  String getDesktopName(HDESK);
+  std::string getDesktopName(HDESK);
 
   // our desk window procs
   static LRESULT CALLBACK primaryDeskProc(HWND, UINT, WPARAM, LPARAM);
@@ -274,7 +275,7 @@ private:
 
   // the current desk and it's name
   Desk *m_activeDesk;
-  String m_activeDeskName;
+  std::string m_activeDeskName;
 
   // one desk per desktop and a cond var to communicate with it
   Mutex m_mutex;
diff --git a/src/lib/platform/MSWindowsKeyState.cpp b/src/lib/platform/MSWindowsKeyState.cpp
index 917767dab..31dfe0c34 100644
--- a/src/lib/platform/MSWindowsKeyState.cpp
+++ b/src/lib/platform/MSWindowsKeyState.cpp
@@ -22,7 +22,6 @@
 #include "base/FunctionJob.h"
 #include "base/IEventQueue.h"
 #include "base/Log.h"
-#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "mt/Thread.h"
 #include "platform/MSWindowsDesks.h"
@@ -569,7 +568,8 @@ static const Win32Modifiers s_modifiers[] = {{VK_SHIFT, KeyModifierShift},
                                              {VK_RWIN, KeyModifierSuper}};
 
 MSWindowsKeyState::MSWindowsKeyState(
-    MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled
+    MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, std::vector<std::string> layouts,
+    bool isLangSyncEnabled
 )
     : KeyState(events, std::move(layouts), isLangSyncEnabled),
       m_eventTarget(eventTarget),
@@ -587,7 +587,7 @@ MSWindowsKeyState::MSWindowsKeyState(
 
 MSWindowsKeyState::MSWindowsKeyState(
     MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, deskflow::KeyMap &keyMap,
-    std::vector<String> layouts, bool isLangSyncEnabled
+    std::vector<std::string> layouts, bool isLangSyncEnabled
 )
     : KeyState(events, keyMap, std::move(layouts), isLangSyncEnabled),
       m_eventTarget(eventTarget),
@@ -749,13 +749,13 @@ void MSWindowsKeyState::sendKeyEvent(
   }
 }
 
-void MSWindowsKeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang)
+void MSWindowsKeyState::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   KeyState::fakeKeyDown(id, mask, button, lang);
 }
 
 bool MSWindowsKeyState::fakeKeyRepeat(
-    KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang
+    KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang
 )
 {
   return KeyState::fakeKeyRepeat(id, mask, count, button, lang);
diff --git a/src/lib/platform/MSWindowsKeyState.h b/src/lib/platform/MSWindowsKeyState.h
index 098e1c876..e1811abc7 100644
--- a/src/lib/platform/MSWindowsKeyState.h
+++ b/src/lib/platform/MSWindowsKeyState.h
@@ -18,10 +18,11 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdvector.h"
 #include "deskflow/KeyState.h"
 
+#include <string>
+
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 
@@ -38,11 +39,12 @@ class MSWindowsKeyState : public KeyState
 {
 public:
   MSWindowsKeyState(
-      MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled
+      MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, std::vector<std::string> layouts,
+      bool isLangSyncEnabled
   );
   MSWindowsKeyState(
       MSWindowsDesks *desks, void *eventTarget, IEventQueue *events, deskflow::KeyMap &keyMap,
-      std::vector<String> layouts, bool isLangSyncEnabled
+      std::vector<std::string> layouts, bool isLangSyncEnabled
   );
   virtual ~MSWindowsKeyState();
 
@@ -140,8 +142,8 @@ public:
   //@}
 
   // IKeyState overrides
-  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang);
-  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang);
+  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang);
+  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang);
   virtual bool fakeCtrlAltDel();
   virtual KeyModifierMask pollActiveModifiers() const;
   virtual SInt32 pollActiveGroup() const;
diff --git a/src/lib/platform/MSWindowsScreen.cpp b/src/lib/platform/MSWindowsScreen.cpp
index f94c93c5f..fa8564249 100644
--- a/src/lib/platform/MSWindowsScreen.cpp
+++ b/src/lib/platform/MSWindowsScreen.cpp
@@ -22,7 +22,6 @@
 #include "arch/win32/ArchMiscWindows.h"
 #include "base/IEventQueue.h"
 #include "base/Log.h"
-#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "base/TMethodJob.h"
 #include "client/Client.h"
@@ -157,7 +156,7 @@ MSWindowsScreen::MSWindowsScreen(
     // SHGetFolderPath is deprecated in vista, but use it for xp support.
     char desktopPath[MAX_PATH];
     if (SUCCEEDED(SHGetFolderPath(NULL, CSIDL_DESKTOP, NULL, 0, desktopPath))) {
-      m_desktopPath = String(desktopPath);
+      m_desktopPath = std::string(desktopPath);
       LOG((CLOG_DEBUG "using desktop for file drag-drop target: %s", m_desktopPath.c_str()));
     } else {
       LOG((CLOG_DEBUG "unable to use desktop as file drag-drop target, code=%d", GetLastError()));
@@ -379,7 +378,7 @@ void MSWindowsScreen::leave()
 
 void MSWindowsScreen::sendDragThread(void *)
 {
-  String &draggingFilename = getDraggingFilename();
+  std::string &draggingFilename = getDraggingFilename();
   size_t size = draggingFilename.size();
 
   if (draggingFilename.empty() == false) {
@@ -791,13 +790,15 @@ void MSWindowsScreen::updateKeys()
   m_desks->updateKeys();
 }
 
-void MSWindowsScreen::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang)
+void MSWindowsScreen::fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   PlatformScreen::fakeKeyDown(id, mask, button, lang);
   updateForceShowCursor();
 }
 
-bool MSWindowsScreen::fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+bool MSWindowsScreen::fakeKeyRepeat(
+    KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang
+)
 {
   bool result = PlatformScreen::fakeKeyRepeat(id, mask, count, button, lang);
   updateForceShowCursor();
@@ -1777,7 +1778,7 @@ void MSWindowsScreen::fakeDraggingFiles(DragFileList fileList)
   // exception from being thrown.
 }
 
-String &MSWindowsScreen::getDraggingFilename()
+std::string &MSWindowsScreen::getDraggingFilename()
 {
   if (m_draggingStarted) {
     m_dropTarget->clearDraggingFilename();
@@ -1796,7 +1797,7 @@ String &MSWindowsScreen::getDraggingFilename()
     fakeKeyUp(1);
     fakeMouseButton(kButtonLeft, false);
 
-    String filename;
+    std::string filename;
     DOUBLE timeout = ARCH->time() + .5f;
     while (ARCH->time() < timeout) {
       ARCH->sleep(.05f);
@@ -1820,16 +1821,15 @@ String &MSWindowsScreen::getDraggingFilename()
       LOG((CLOG_DEBUG "failed to get drag file name from OLE"));
     }
   }
-
   return m_draggingFilename;
 }
 
-const String &MSWindowsScreen::getDropTarget() const
+const std::string &MSWindowsScreen::getDropTarget() const
 {
   return m_desktopPath;
 }
 
-String MSWindowsScreen::getSecureInputApp() const
+std::string MSWindowsScreen::getSecureInputApp() const
 {
   // ignore on Windows
   return "";
diff --git a/src/lib/platform/MSWindowsScreen.h b/src/lib/platform/MSWindowsScreen.h
index 6b0381352..b915b1623 100644
--- a/src/lib/platform/MSWindowsScreen.h
+++ b/src/lib/platform/MSWindowsScreen.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/ClientArgs.h"
 #include "deskflow/DragInformation.h"
 #include "deskflow/PlatformScreen.h"
@@ -28,6 +27,8 @@
 #include "platform/MSWindowsPowerManager.h"
 #include "platform/dfwhook.h"
 
+#include <string>
+
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
 
@@ -115,8 +116,8 @@ public:
 
   // IKeyState overrides
   virtual void updateKeys();
-  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang);
-  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang);
+  virtual void fakeKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang);
+  virtual bool fakeKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang);
   virtual bool fakeKeyUp(KeyButton button);
   virtual void fakeAllKeysUp();
 
@@ -136,9 +137,9 @@ public:
   virtual void setSequenceNumber(UInt32);
   virtual bool isPrimary() const;
   virtual void fakeDraggingFiles(DragFileList fileList);
-  virtual String &getDraggingFilename();
-  virtual const String &getDropTarget() const;
-  String getSecureInputApp() const override;
+  virtual std::string &getDraggingFilename();
+  virtual const std::string &getDropTarget() const;
+  std::string getSecureInputApp() const override;
 
 protected:
   // IPlatformScreen overrides
@@ -354,7 +355,7 @@ private:
 
   IEventQueue *m_events;
 
-  String m_desktopPath;
+  std::string m_desktopPath;
 
   MSWindowsDropTarget *m_dropTarget;
   HWND m_dropWindow;
diff --git a/src/lib/platform/MSWindowsScreenSaver.h b/src/lib/platform/MSWindowsScreenSaver.h
index 9303c7a27..eac1d2af3 100644
--- a/src/lib/platform/MSWindowsScreenSaver.h
+++ b/src/lib/platform/MSWindowsScreenSaver.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/IScreenSaver.h"
 
 #define WIN32_LEAN_AND_MEAN
diff --git a/src/lib/platform/MSWindowsSession.cpp b/src/lib/platform/MSWindowsSession.cpp
index 4419cf442..14fdfa516 100644
--- a/src/lib/platform/MSWindowsSession.cpp
+++ b/src/lib/platform/MSWindowsSession.cpp
@@ -170,9 +170,9 @@ BOOL MSWindowsSession::nextProcessEntry(HANDLE snapshot, LPPROCESSENTRY32 entry)
   return gotEntry;
 }
 
-String MSWindowsSession::getActiveDesktopName()
+std::string MSWindowsSession::getActiveDesktopName()
 {
-  String result;
+  std::string result;
   try {
     HDESK hd = OpenInputDesktop(0, TRUE, GENERIC_READ);
     if (hd != NULL) {
diff --git a/src/lib/platform/MSWindowsSession.h b/src/lib/platform/MSWindowsSession.h
index 3cf450ad9..3563892df 100644
--- a/src/lib/platform/MSWindowsSession.h
+++ b/src/lib/platform/MSWindowsSession.h
@@ -17,7 +17,7 @@
 
 #pragma once
 
-#include "base/String.h"
+#include <string>
 
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
@@ -48,7 +48,7 @@ public:
 
   void updateActiveSession();
 
-  String getActiveDesktopName();
+  std::string getActiveDesktopName();
 
 private:
   BOOL nextProcessEntry(HANDLE snapshot, LPPROCESSENTRY32 entry);
diff --git a/src/lib/platform/MSWindowsUtil.cpp b/src/lib/platform/MSWindowsUtil.cpp
index dd6adecf7..b1cefa362 100644
--- a/src/lib/platform/MSWindowsUtil.cpp
+++ b/src/lib/platform/MSWindowsUtil.cpp
@@ -26,29 +26,29 @@
 // MSWindowsUtil
 //
 
-String MSWindowsUtil::getString(HINSTANCE instance, DWORD id)
+std::string MSWindowsUtil::getString(HINSTANCE instance, DWORD id)
 {
   char *msg = NULL;
   int n = LoadString(instance, id, reinterpret_cast<LPSTR>(&msg), 0);
 
   if (n <= 0) {
-    return String();
+    return std::string();
   }
 
-  return String(msg, n);
+  return std::string(msg, n);
 }
 
-String MSWindowsUtil::getErrorString(HINSTANCE hinstance, DWORD error, DWORD id)
+std::string MSWindowsUtil::getErrorString(HINSTANCE hinstance, DWORD error, DWORD id)
 {
   char *buffer;
   if (FormatMessage(
           FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM, 0, error,
           MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&buffer, 0, NULL
       ) == 0) {
-    String errorString = deskflow::string::sprintf("%d", error);
+    std::string errorString = deskflow::string::sprintf("%d", error);
     return deskflow::string::format(getString(hinstance, id).c_str(), errorString.c_str());
   } else {
-    String result(buffer);
+    std::string result(buffer);
     LocalFree(buffer);
     return result;
   }
diff --git a/src/lib/platform/MSWindowsUtil.h b/src/lib/platform/MSWindowsUtil.h
index bb0fadad5..5dc43a163 100644
--- a/src/lib/platform/MSWindowsUtil.h
+++ b/src/lib/platform/MSWindowsUtil.h
@@ -18,7 +18,7 @@
 
 #pragma once
 
-#include "base/String.h"
+#include <string>
 
 #define WINDOWS_LEAN_AND_MEAN
 #include <Windows.h>
@@ -30,12 +30,12 @@ public:
   /*!
   Gets a string for \p id from the string table of \p instance.
   */
-  static String getString(HINSTANCE instance, DWORD id);
+  static std::string getString(HINSTANCE instance, DWORD id);
 
   //! Get error string
   /*!
   Gets a system error message for \p error.  If the error cannot be
   found return the string for \p id, replacing ${1} with \p error.
   */
-  static String getErrorString(HINSTANCE, DWORD error, DWORD id);
+  static std::string getErrorString(HINSTANCE, DWORD error, DWORD id);
 };
diff --git a/src/lib/platform/MSWindowsWatchdog.cpp b/src/lib/platform/MSWindowsWatchdog.cpp
index a565e4427..4b2e00ff7 100644
--- a/src/lib/platform/MSWindowsWatchdog.cpp
+++ b/src/lib/platform/MSWindowsWatchdog.cpp
@@ -21,6 +21,7 @@
 #include "arch/Arch.h"
 #include "arch/win32/XArchWindows.h"
 #include "base/Log.h"
+#include "base/String.h"
 #include "base/TMethodJob.h"
 #include "base/log_outputters.h"
 #include "common/ipc.h"
@@ -380,7 +381,7 @@ void MSWindowsWatchdog::setStartupInfo(STARTUPINFO &si)
   si.dwFlags |= STARTF_USESTDHANDLES;
 }
 
-BOOL MSWindowsWatchdog::startProcessInForeground(String &command)
+BOOL MSWindowsWatchdog::startProcessInForeground(std::string &command)
 {
   // clear, as we're reusing process info struct
   ZeroMemory(&m_processInfo, sizeof(PROCESS_INFORMATION));
@@ -400,7 +401,7 @@ BOOL MSWindowsWatchdog::startProcessInForeground(String &command)
   return result;
 }
 
-BOOL MSWindowsWatchdog::startProcessAsUser(String &command, HANDLE userToken, LPSECURITY_ATTRIBUTES sa)
+BOOL MSWindowsWatchdog::startProcessAsUser(std::string &command, HANDLE userToken, LPSECURITY_ATTRIBUTES sa)
 {
   // clear, as we're reusing process info struct
   ZeroMemory(&m_processInfo, sizeof(PROCESS_INFORMATION));
@@ -601,24 +602,24 @@ void MSWindowsWatchdog::shutdownExistingProcesses()
 
 void MSWindowsWatchdog::getActiveDesktop(LPSECURITY_ATTRIBUTES security)
 {
-  String installedDir = ARCH->getInstalledDirectory();
+  std::string installedDir = ARCH->getInstalledDirectory();
   if (!installedDir.empty()) {
     MSWindowsSession session;
-    String name = session.getActiveDesktopName();
+    std::string name = session.getActiveDesktopName();
     if (name.empty()) {
       LOG((CLOG_CRIT "failed to get active desktop name"));
     } else {
-      String output = deskflow::string::sprintf("activeDesktop:%s", name.c_str());
+      std::string output = deskflow::string::sprintf("activeDesktop:%s", name.c_str());
       LOG((CLOG_INFO "%s", output.c_str()));
     }
   }
 }
 
-void MSWindowsWatchdog::testOutput(String buffer)
+void MSWindowsWatchdog::testOutput(std::string buffer)
 {
   // HACK: check standard output seems hacky.
   size_t i = buffer.find(g_activeDesktop);
-  if (i != String::npos) {
+  if (i != std::string::npos) {
     size_t s = sizeof(g_activeDesktop);
     std::string defaultScreen = "Default";
     m_activeDesktop = trimDesktopName(buffer.substr(i + s - 1));
diff --git a/src/lib/platform/MSWindowsWatchdog.h b/src/lib/platform/MSWindowsWatchdog.h
index be94c0f25..eec3cba70 100644
--- a/src/lib/platform/MSWindowsWatchdog.h
+++ b/src/lib/platform/MSWindowsWatchdog.h
@@ -54,11 +54,11 @@ private:
   HANDLE duplicateProcessToken(HANDLE process, LPSECURITY_ATTRIBUTES security);
   HANDLE getUserToken(LPSECURITY_ATTRIBUTES security);
   void startProcess();
-  BOOL startProcessAsUser(String &command, HANDLE userToken, LPSECURITY_ATTRIBUTES sa);
-  BOOL startProcessInForeground(String &command);
+  BOOL startProcessAsUser(std::string &command, HANDLE userToken, LPSECURITY_ATTRIBUTES sa);
+  BOOL startProcessInForeground(std::string &command);
   void sendSas();
   void getActiveDesktop(LPSECURITY_ATTRIBUTES security);
-  void testOutput(String buffer);
+  void testOutput(std::string buffer);
   void setStartupInfo(STARTUPINFO &si);
   void checkChildren();
   /**
@@ -111,12 +111,12 @@ An error occured in the process watchdog.
 class XMSWindowsWatchdogError : public XDeskflow
 {
 public:
-  XMSWindowsWatchdogError(const String &msg) : XDeskflow(msg)
+  XMSWindowsWatchdogError(const std::string &msg) : XDeskflow(msg)
   {
   }
 
   // XBase overrides
-  virtual String getWhat() const throw()
+  virtual std::string getWhat() const throw()
   {
     return what();
   }
diff --git a/src/lib/platform/OSXClipboard.cpp b/src/lib/platform/OSXClipboard.cpp
index b31f71b0e..d6b7fc3ae 100644
--- a/src/lib/platform/OSXClipboard.cpp
+++ b/src/lib/platform/OSXClipboard.cpp
@@ -87,7 +87,7 @@ bool OSXClipboard::synchronize()
   return false;
 }
 
-void OSXClipboard::add(EFormat format, const String &data)
+void OSXClipboard::add(EFormat format, const std::string &data)
 {
   if (m_pboard == NULL)
     return;
@@ -107,7 +107,7 @@ void OSXClipboard::add(EFormat format, const String &data)
 
     // skip converters for other formats
     if (converter->getFormat() == format) {
-      String osXData = converter->fromIClipboard(data);
+      std::string osXData = converter->fromIClipboard(data);
       CFStringRef flavorType = converter->getOSXFormat();
       CFDataRef dataRef = CFDataCreate(kCFAllocatorDefault, (UInt8 *)osXData.data(), osXData.size());
       PasteboardItemID itemID = 0;
@@ -168,11 +168,11 @@ bool OSXClipboard::has(EFormat format) const
   return false;
 }
 
-String OSXClipboard::get(EFormat format) const
+std::string OSXClipboard::get(EFormat format) const
 {
   CFStringRef type;
   PasteboardItemID item;
-  String result;
+  std::string result;
 
   if (m_pboard == NULL)
     return result;
@@ -208,7 +208,7 @@ String OSXClipboard::get(EFormat format) const
       throw err;
     }
 
-    result = String((char *)CFDataGetBytePtr(buffer), CFDataGetLength(buffer));
+    result = std::string((char *)CFDataGetBytePtr(buffer), CFDataGetLength(buffer));
   } catch (OSStatus err) {
     LOG((CLOG_DEBUG "exception thrown in OSXClipboard::get MacError (%d)", err));
   } catch (...) {
diff --git a/src/lib/platform/OSXClipboard.h b/src/lib/platform/OSXClipboard.h
index 447f1a417..f58c3ffbc 100644
--- a/src/lib/platform/OSXClipboard.h
+++ b/src/lib/platform/OSXClipboard.h
@@ -37,12 +37,12 @@ public:
 
   // IClipboard overrides
   virtual bool empty();
-  virtual void add(EFormat, const String &data);
+  virtual void add(EFormat, const std::string &data);
   virtual bool open(Time) const;
   virtual void close() const;
   virtual Time getTime() const;
   virtual bool has(EFormat) const;
-  virtual String get(EFormat) const;
+  virtual std::string get(EFormat) const;
 
   bool synchronize();
 
@@ -83,14 +83,14 @@ public:
   getFormat().  The return data will be in the scrap
   format returned by getOSXFormat().
   */
-  virtual String fromIClipboard(const String &) const = 0;
+  virtual std::string fromIClipboard(const std::string &) const = 0;
 
   //! Convert to IClipboard format
   /*!
   Convert from the carbon scrap format to the IClipboard format
   (i.e., the reverse of fromIClipboard()).
   */
-  virtual String toIClipboard(const String &) const = 0;
+  virtual std::string toIClipboard(const std::string &) const = 0;
 
   //@}
 };
diff --git a/src/lib/platform/OSXClipboardAnyBitmapConverter.cpp b/src/lib/platform/OSXClipboardAnyBitmapConverter.cpp
index 400b09716..3269b8422 100644
--- a/src/lib/platform/OSXClipboardAnyBitmapConverter.cpp
+++ b/src/lib/platform/OSXClipboardAnyBitmapConverter.cpp
@@ -34,12 +34,12 @@ IClipboard::EFormat OSXClipboardAnyBitmapConverter::getFormat() const
   return IClipboard::kBitmap;
 }
 
-String OSXClipboardAnyBitmapConverter::fromIClipboard(const String &data) const
+std::string OSXClipboardAnyBitmapConverter::fromIClipboard(const std::string &data) const
 {
   return doFromIClipboard(data);
 }
 
-String OSXClipboardAnyBitmapConverter::toIClipboard(const String &data) const
+std::string OSXClipboardAnyBitmapConverter::toIClipboard(const std::string &data) const
 {
   return doToIClipboard(data);
 }
diff --git a/src/lib/platform/OSXClipboardAnyBitmapConverter.h b/src/lib/platform/OSXClipboardAnyBitmapConverter.h
index f5e5b0898..0e347e75a 100644
--- a/src/lib/platform/OSXClipboardAnyBitmapConverter.h
+++ b/src/lib/platform/OSXClipboardAnyBitmapConverter.h
@@ -30,19 +30,19 @@ public:
   // IOSXClipboardConverter overrides
   virtual IClipboard::EFormat getFormat() const;
   virtual CFStringRef getOSXFormat() const = 0;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 protected:
   //! Convert from IClipboard format
   /*!
    Do UTF-8 conversion and linefeed conversion.
   */
-  virtual String doFromIClipboard(const String &) const = 0;
+  virtual std::string doFromIClipboard(const std::string &) const = 0;
 
   //! Convert to IClipboard format
   /*!
    Do UTF-8 conversion and Linefeed conversion.
   */
-  virtual String doToIClipboard(const String &) const = 0;
+  virtual std::string doToIClipboard(const std::string &) const = 0;
 };
diff --git a/src/lib/platform/OSXClipboardAnyTextConverter.cpp b/src/lib/platform/OSXClipboardAnyTextConverter.cpp
index 3c8721dd4..3dee0c22e 100644
--- a/src/lib/platform/OSXClipboardAnyTextConverter.cpp
+++ b/src/lib/platform/OSXClipboardAnyTextConverter.cpp
@@ -39,13 +39,13 @@ IClipboard::EFormat OSXClipboardAnyTextConverter::getFormat() const
   return IClipboard::kText;
 }
 
-String OSXClipboardAnyTextConverter::fromIClipboard(const String &data) const
+std::string OSXClipboardAnyTextConverter::fromIClipboard(const std::string &data) const
 {
   // convert linefeeds and then convert to desired encoding
   return doFromIClipboard(convertLinefeedToMacOS(data));
 }
 
-String OSXClipboardAnyTextConverter::toIClipboard(const String &data) const
+std::string OSXClipboardAnyTextConverter::toIClipboard(const std::string &data) const
 {
   // convert text then newlines
   return convertLinefeedToUnix(doToIClipboard(data));
@@ -61,19 +61,19 @@ static bool isCR(char ch)
   return (ch == '\r');
 }
 
-String OSXClipboardAnyTextConverter::convertLinefeedToMacOS(const String &src)
+std::string OSXClipboardAnyTextConverter::convertLinefeedToMacOS(const std::string &src)
 {
   // note -- we assume src is a valid UTF-8 string
-  String copy = src;
+  std::string copy = src;
 
   std::replace_if(copy.begin(), copy.end(), isLF, '\r');
 
   return copy;
 }
 
-String OSXClipboardAnyTextConverter::convertLinefeedToUnix(const String &src)
+std::string OSXClipboardAnyTextConverter::convertLinefeedToUnix(const std::string &src)
 {
-  String copy = src;
+  std::string copy = src;
 
   std::replace_if(copy.begin(), copy.end(), isCR, '\n');
 
diff --git a/src/lib/platform/OSXClipboardAnyTextConverter.h b/src/lib/platform/OSXClipboardAnyTextConverter.h
index 9d7a18da3..10eb630e5 100644
--- a/src/lib/platform/OSXClipboardAnyTextConverter.h
+++ b/src/lib/platform/OSXClipboardAnyTextConverter.h
@@ -30,23 +30,23 @@ public:
   // IOSXClipboardConverter overrides
   virtual IClipboard::EFormat getFormat() const;
   virtual CFStringRef getOSXFormat() const = 0;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 protected:
   //! Convert from IClipboard format
   /*!
   Do UTF-8 conversion and linefeed conversion.
   */
-  virtual String doFromIClipboard(const String &) const = 0;
+  virtual std::string doFromIClipboard(const std::string &) const = 0;
 
   //! Convert to IClipboard format
   /*!
   Do UTF-8 conversion and Linefeed conversion.
   */
-  virtual String doToIClipboard(const String &) const = 0;
+  virtual std::string doToIClipboard(const std::string &) const = 0;
 
 private:
-  static String convertLinefeedToMacOS(const String &);
-  static String convertLinefeedToUnix(const String &);
+  static std::string convertLinefeedToMacOS(const std::string &);
+  static std::string convertLinefeedToUnix(const std::string &);
 };
diff --git a/src/lib/platform/OSXClipboardBMPConverter.cpp b/src/lib/platform/OSXClipboardBMPConverter.cpp
index 076bdabe4..b2088f797 100644
--- a/src/lib/platform/OSXClipboardBMPConverter.cpp
+++ b/src/lib/platform/OSXClipboardBMPConverter.cpp
@@ -80,7 +80,7 @@ CFStringRef OSXClipboardBMPConverter::getOSXFormat() const
   return CFSTR("com.microsoft.bmp");
 }
 
-String OSXClipboardBMPConverter::fromIClipboard(const String &bmp) const
+std::string OSXClipboardBMPConverter::fromIClipboard(const std::string &bmp) const
 {
   LOG((CLOG_DEBUG1 "getting data from clipboard"));
   // create BMP image
@@ -92,20 +92,20 @@ String OSXClipboardBMPConverter::fromIClipboard(const String &bmp) const
   toLE(dst, static_cast<UInt16>(0));
   toLE(dst, static_cast<UInt16>(0));
   toLE(dst, static_cast<UInt32>(14 + 40));
-  return String(reinterpret_cast<const char *>(header), 14) + bmp;
+  return std::string(reinterpret_cast<const char *>(header), 14) + bmp;
 }
 
-String OSXClipboardBMPConverter::toIClipboard(const String &bmp) const
+std::string OSXClipboardBMPConverter::toIClipboard(const std::string &bmp) const
 {
   // make sure data is big enough for a BMP file
   if (bmp.size() <= 14 + 40) {
-    return String();
+    return std::string();
   }
 
   // check BMP file header
   const UInt8 *rawBMPHeader = reinterpret_cast<const UInt8 *>(bmp.data());
   if (rawBMPHeader[0] != 'B' || rawBMPHeader[1] != 'M') {
-    return String();
+    return std::string();
   }
 
   // get offset to image data
diff --git a/src/lib/platform/OSXClipboardBMPConverter.h b/src/lib/platform/OSXClipboardBMPConverter.h
index 21ff5656d..dc73ec8c4 100644
--- a/src/lib/platform/OSXClipboardBMPConverter.h
+++ b/src/lib/platform/OSXClipboardBMPConverter.h
@@ -33,9 +33,9 @@ public:
   virtual CFStringRef getOSXFormat() const;
 
   // OSXClipboardAnyBMPConverter overrides
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
   // generic encoding converter
-  static String convertString(const String &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
+  static std::string convertString(const std::string &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
 };
diff --git a/src/lib/platform/OSXClipboardHTMLConverter.cpp b/src/lib/platform/OSXClipboardHTMLConverter.cpp
index 5a4685dc5..d7052658a 100644
--- a/src/lib/platform/OSXClipboardHTMLConverter.cpp
+++ b/src/lib/platform/OSXClipboardHTMLConverter.cpp
@@ -40,13 +40,14 @@ CFStringRef OSXClipboardHTMLConverter::getOSXFormat() const
   return CFSTR("public.html");
 }
 
-String
-OSXClipboardHTMLConverter::convertString(const String &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding)
+std::string OSXClipboardHTMLConverter::convertString(
+    const std::string &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding
+)
 {
   CFStringRef stringRef = CFStringCreateWithCString(kCFAllocatorDefault, data.c_str(), fromEncoding);
 
   if (stringRef == NULL) {
-    return String();
+    return std::string();
   }
 
   CFIndex buffSize;
@@ -58,12 +59,12 @@ OSXClipboardHTMLConverter::convertString(const String &data, CFStringEncoding fr
 
   if (buffer == NULL) {
     CFRelease(stringRef);
-    return String();
+    return std::string();
   }
 
   CFStringGetBytes(stringRef, entireString, toEncoding, 0, false, (UInt8 *)buffer, buffSize, NULL);
 
-  String result(buffer, buffSize);
+  std::string result(buffer, buffSize);
 
   delete[] buffer;
   CFRelease(stringRef);
@@ -71,12 +72,12 @@ OSXClipboardHTMLConverter::convertString(const String &data, CFStringEncoding fr
   return result;
 }
 
-String OSXClipboardHTMLConverter::doFromIClipboard(const String &data) const
+std::string OSXClipboardHTMLConverter::doFromIClipboard(const std::string &data) const
 {
   return data;
 }
 
-String OSXClipboardHTMLConverter::doToIClipboard(const String &data) const
+std::string OSXClipboardHTMLConverter::doToIClipboard(const std::string &data) const
 {
   if (Unicode::isUTF8(data)) {
     return data;
diff --git a/src/lib/platform/OSXClipboardHTMLConverter.h b/src/lib/platform/OSXClipboardHTMLConverter.h
index e3a687a6a..4c8b01cb9 100644
--- a/src/lib/platform/OSXClipboardHTMLConverter.h
+++ b/src/lib/platform/OSXClipboardHTMLConverter.h
@@ -34,9 +34,9 @@ public:
 
 protected:
   // OSXClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 
   // generic encoding converter
-  static String convertString(const String &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
+  static std::string convertString(const std::string &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
 };
diff --git a/src/lib/platform/OSXClipboardTextConverter.cpp b/src/lib/platform/OSXClipboardTextConverter.cpp
index 5d5e1acc0..9dcfc0480 100644
--- a/src/lib/platform/OSXClipboardTextConverter.cpp
+++ b/src/lib/platform/OSXClipboardTextConverter.cpp
@@ -39,13 +39,14 @@ CFStringRef OSXClipboardTextConverter::getOSXFormat() const
   return CFSTR("public.plain-text");
 }
 
-String
-OSXClipboardTextConverter::convertString(const String &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding)
+std::string OSXClipboardTextConverter::convertString(
+    const std::string &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding
+)
 {
   CFStringRef stringRef = CFStringCreateWithCString(kCFAllocatorDefault, data.c_str(), fromEncoding);
 
   if (stringRef == NULL) {
-    return String();
+    return std::string();
   }
 
   CFIndex buffSize;
@@ -57,12 +58,12 @@ OSXClipboardTextConverter::convertString(const String &data, CFStringEncoding fr
 
   if (buffer == NULL) {
     CFRelease(stringRef);
-    return String();
+    return std::string();
   }
 
   CFStringGetBytes(stringRef, entireString, toEncoding, 0, false, (UInt8 *)buffer, buffSize, NULL);
 
-  String result(buffer, buffSize);
+  std::string result(buffer, buffSize);
 
   delete[] buffer;
   CFRelease(stringRef);
@@ -70,12 +71,12 @@ OSXClipboardTextConverter::convertString(const String &data, CFStringEncoding fr
   return result;
 }
 
-String OSXClipboardTextConverter::doFromIClipboard(const String &data) const
+std::string OSXClipboardTextConverter::doFromIClipboard(const std::string &data) const
 {
   return convertString(data, kCFStringEncodingUTF8, CFStringGetSystemEncoding());
 }
 
-String OSXClipboardTextConverter::doToIClipboard(const String &data) const
+std::string OSXClipboardTextConverter::doToIClipboard(const std::string &data) const
 {
   return convertString(data, CFStringGetSystemEncoding(), kCFStringEncodingUTF8);
 }
diff --git a/src/lib/platform/OSXClipboardTextConverter.h b/src/lib/platform/OSXClipboardTextConverter.h
index ff048f3fe..dc1cf6ab3 100644
--- a/src/lib/platform/OSXClipboardTextConverter.h
+++ b/src/lib/platform/OSXClipboardTextConverter.h
@@ -32,9 +32,9 @@ public:
 
 protected:
   // OSXClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 
   // generic encoding converter
-  static String convertString(const String &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
+  static std::string convertString(const std::string &data, CFStringEncoding fromEncoding, CFStringEncoding toEncoding);
 };
diff --git a/src/lib/platform/OSXClipboardUTF16Converter.cpp b/src/lib/platform/OSXClipboardUTF16Converter.cpp
index f9c707091..bb2d2dea2 100644
--- a/src/lib/platform/OSXClipboardUTF16Converter.cpp
+++ b/src/lib/platform/OSXClipboardUTF16Converter.cpp
@@ -39,13 +39,13 @@ CFStringRef OSXClipboardUTF16Converter::getOSXFormat() const
   return CFSTR("public.utf16-plain-text");
 }
 
-String OSXClipboardUTF16Converter::doFromIClipboard(const String &data) const
+std::string OSXClipboardUTF16Converter::doFromIClipboard(const std::string &data) const
 {
   // convert and add nul terminator
   return Unicode::UTF8ToUTF16(data);
 }
 
-String OSXClipboardUTF16Converter::doToIClipboard(const String &data) const
+std::string OSXClipboardUTF16Converter::doToIClipboard(const std::string &data) const
 {
   // convert and strip nul terminator
   return Unicode::UTF16ToUTF8(data);
diff --git a/src/lib/platform/OSXClipboardUTF16Converter.h b/src/lib/platform/OSXClipboardUTF16Converter.h
index 052837000..035191f3d 100644
--- a/src/lib/platform/OSXClipboardUTF16Converter.h
+++ b/src/lib/platform/OSXClipboardUTF16Converter.h
@@ -32,6 +32,6 @@ public:
 
 protected:
   // OSXClipboardAnyTextConverter overrides
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 };
diff --git a/src/lib/platform/OSXClipboardUTF8Converter.cpp b/src/lib/platform/OSXClipboardUTF8Converter.cpp
index 0aeb97432..1f6f6bbd8 100644
--- a/src/lib/platform/OSXClipboardUTF8Converter.cpp
+++ b/src/lib/platform/OSXClipboardUTF8Converter.cpp
@@ -5,12 +5,12 @@ CFStringRef OSXClipboardUTF8Converter::getOSXFormat() const
   return CFSTR("public.utf8-plain-text");
 }
 
-String OSXClipboardUTF8Converter::doFromIClipboard(const String &data) const
+std::string OSXClipboardUTF8Converter::doFromIClipboard(const std::string &data) const
 {
   return data;
 }
 
-String OSXClipboardUTF8Converter::doToIClipboard(const String &data) const
+std::string OSXClipboardUTF8Converter::doToIClipboard(const std::string &data) const
 {
   return data;
 }
diff --git a/src/lib/platform/OSXClipboardUTF8Converter.h b/src/lib/platform/OSXClipboardUTF8Converter.h
index fb97ff72a..70993fc10 100644
--- a/src/lib/platform/OSXClipboardUTF8Converter.h
+++ b/src/lib/platform/OSXClipboardUTF8Converter.h
@@ -25,6 +25,6 @@ public:
   virtual CFStringRef getOSXFormat() const;
 
 private:
-  virtual String doFromIClipboard(const String &) const;
-  virtual String doToIClipboard(const String &) const;
+  virtual std::string doFromIClipboard(const std::string &) const;
+  virtual std::string doToIClipboard(const std::string &) const;
 };
diff --git a/src/lib/platform/OSXKeyState.cpp b/src/lib/platform/OSXKeyState.cpp
index 0852c6d22..8e50492ef 100644
--- a/src/lib/platform/OSXKeyState.cpp
+++ b/src/lib/platform/OSXKeyState.cpp
@@ -190,14 +190,14 @@ bool isModifier(UInt8 virtualKey)
 // OSXKeyState
 //
 
-OSXKeyState::OSXKeyState(IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled)
+OSXKeyState::OSXKeyState(IEventQueue *events, std::vector<std::string> layouts, bool isLangSyncEnabled)
     : KeyState(events, std::move(layouts), isLangSyncEnabled)
 {
   init();
 }
 
 OSXKeyState::OSXKeyState(
-    IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<String> layouts, bool isLangSyncEnabled
+    IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<std::string> layouts, bool isLangSyncEnabled
 )
     : KeyState(events, keyMap, std::move(layouts), isLangSyncEnabled)
 {
diff --git a/src/lib/platform/OSXKeyState.h b/src/lib/platform/OSXKeyState.h
index 226ca15ff..bd79042a6 100644
--- a/src/lib/platform/OSXKeyState.h
+++ b/src/lib/platform/OSXKeyState.h
@@ -37,8 +37,8 @@ class OSXKeyState : public KeyState
 public:
   using KeyIDs = std::vector<KeyID>;
 
-  OSXKeyState(IEventQueue *events, std::vector<String> layouts, bool isLangSyncEnabled);
-  OSXKeyState(IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<String> layouts, bool isLangSyncEnabled);
+  OSXKeyState(IEventQueue *events, std::vector<std::string> layouts, bool isLangSyncEnabled);
+  OSXKeyState(IEventQueue *events, deskflow::KeyMap &keyMap, std::vector<std::string> layouts, bool isLangSyncEnabled);
   virtual ~OSXKeyState();
 
   //! @name modifiers
diff --git a/src/lib/platform/OSXScreen.h b/src/lib/platform/OSXScreen.h
index 38d2eed80..1a28dd967 100644
--- a/src/lib/platform/OSXScreen.h
+++ b/src/lib/platform/OSXScreen.h
@@ -105,10 +105,10 @@ public:
   void setSequenceNumber(UInt32) override;
   bool isPrimary() const override;
   void fakeDraggingFiles(DragFileList fileList) override;
-  String &getDraggingFilename() override;
-  String getSecureInputApp() const override;
+  std::string &getDraggingFilename() override;
+  std::string getSecureInputApp() const override;
 
-  const String &getDropTarget() const override
+  const std::string &getDropTarget() const override
   {
     return m_dropTarget;
   }
@@ -337,7 +337,7 @@ private:
   IEventQueue *m_events;
 
   std::unique_ptr<Thread> m_getDropTargetThread;
-  String m_dropTarget;
+  std::string m_dropTarget;
 
 #if defined(MAC_OS_X_VERSION_10_7)
   Mutex *m_carbonLoopMutex;
diff --git a/src/lib/platform/OSXScreen.mm b/src/lib/platform/OSXScreen.mm
index a2bf45842..1c2846582 100644
--- a/src/lib/platform/OSXScreen.mm
+++ b/src/lib/platform/OSXScreen.mm
@@ -72,7 +72,7 @@ enum
 };
 
 int getSecureInputEventPID();
-String getProcessName(int pid);
+std::string getProcessName(int pid);
 
 // TODO: upgrade deprecated function usage in these functions.
 void setZeroSuppressionInterval();
@@ -837,7 +837,7 @@ void OSXScreen::leave()
   hideCursor();
 
   if (isDraggingStarted()) {
-    String &fileList = getDraggingFilename();
+    std::string &fileList = getDraggingFilename();
 
     if (!m_isPrimary) {
       if (fileList.empty() == false) {
@@ -848,7 +848,7 @@ void OSXScreen::leave()
         di.setFilename(fileList);
         DragFileList dragFileList;
         dragFileList.push_back(di);
-        String info;
+        std::string info;
         UInt32 fileCount = DragInformation::setupDragInfo(dragFileList, info);
         client->sendDragInfo(fileCount, info, info.size());
         LOG((CLOG_DEBUG "send dragging file to server"));
@@ -1918,7 +1918,7 @@ char *OSXScreen::CFStringRefToUTF8String(CFStringRef aString)
 void OSXScreen::fakeDraggingFiles(DragFileList fileList)
 {
   m_fakeDraggingStarted = true;
-  String fileExt;
+  std::string fileExt;
   if (fileList.size() == 1) {
     fileExt = DragInformation::getDragFileExtension(fileList.at(0).getFilename());
   }
@@ -1930,7 +1930,7 @@ void OSXScreen::fakeDraggingFiles(DragFileList fileList)
 #endif
 }
 
-String &OSXScreen::getDraggingFilename()
+std::string &OSXScreen::getDraggingFilename()
 {
   if (m_draggingStarted) {
     m_draggingFilename.clear();
@@ -1977,7 +1977,7 @@ void OSXScreen::waitForCarbonLoop() const
 #endif
 }
 
-String OSXScreen::getSecureInputApp() const
+std::string OSXScreen::getSecureInputApp() const
 {
   if (IsSecureEventInputEnabled()) {
     int secureInputProcessPID = getSecureInputEventPID();
@@ -2044,7 +2044,7 @@ int getSecureInputEventPID()
   return pid;
 }
 
-String getProcessName(int pid)
+std::string getProcessName(int pid)
 {
   if (!pid)
     return "";
diff --git a/src/lib/platform/XWindowsClipboard.cpp b/src/lib/platform/XWindowsClipboard.cpp
index 57035af1c..e352b42cc 100644
--- a/src/lib/platform/XWindowsClipboard.cpp
+++ b/src/lib/platform/XWindowsClipboard.cpp
@@ -153,7 +153,7 @@ bool XWindowsClipboard::addSimpleRequest(Window requestor, Atom target, ::Time t
   }
 
   // handle targets
-  String data;
+  std::string data;
   Atom type = None;
   int format = 0;
   if (target == m_atomTargets) {
@@ -278,7 +278,7 @@ bool XWindowsClipboard::empty()
   return true;
 }
 
-void XWindowsClipboard::add(EFormat format, const String &data)
+void XWindowsClipboard::add(EFormat format, const std::string &data)
 {
   assert(m_open);
   assert(m_owner);
@@ -357,7 +357,7 @@ bool XWindowsClipboard::has(EFormat format) const
   return m_added[format];
 }
 
-String XWindowsClipboard::get(EFormat format) const
+std::string XWindowsClipboard::get(EFormat format) const
 {
   assert(m_open);
 
@@ -468,7 +468,7 @@ void XWindowsClipboard::icccmFillCache()
   // instead of the correct type ATOM;  allow either.
   const Atom atomTargets = m_atomTargets;
   Atom target;
-  String data;
+  std::string data;
   if (!icccmGetSelection(atomTargets, &target, &data) || (target != m_atomAtom && target != m_atomTargets)) {
     LOG((CLOG_DEBUG1 "selection doesn't support TARGETS"));
     data = "";
@@ -510,7 +510,7 @@ void XWindowsClipboard::icccmFillCache()
 
     // get the data
     Atom actualTarget;
-    String targetData;
+    std::string targetData;
     if (!icccmGetSelection(target, &actualTarget, &targetData)) {
       LOG((CLOG_DEBUG1 "  no data for target %s", XWindowsUtil::atomToString(m_display, target).c_str()));
       continue;
@@ -528,7 +528,7 @@ void XWindowsClipboard::icccmFillCache()
   }
 }
 
-bool XWindowsClipboard::icccmGetSelection(Atom target, Atom *actualTarget, String *data) const
+bool XWindowsClipboard::icccmGetSelection(Atom target, Atom *actualTarget, std::string *data) const
 {
   assert(actualTarget != nullptr);
   assert(data != nullptr);
@@ -550,7 +550,7 @@ bool XWindowsClipboard::icccmGetSelection(Atom target, Atom *actualTarget, Strin
 IClipboard::Time XWindowsClipboard::icccmGetTime() const
 {
   Atom actualTarget;
-  String data;
+  std::string data;
   if (icccmGetSelection(m_atomTimestamp, &actualTarget, &data) && actualTarget == m_atomInteger) {
     Time time = *static_cast<const Time *>(static_cast<const void *>(data.data()));
     LOG((CLOG_DEBUG1 "got ICCCM time %d", time));
@@ -616,7 +616,7 @@ bool XWindowsClipboard::motifOwnsClipboard() const
   // get the Motif clipboard header property from the root window
   Atom target;
   SInt32 format;
-  String data;
+  std::string data;
   Window root = RootWindow(m_display, DefaultScreen(m_display));
   if (!XWindowsUtil::getWindowProperty(m_display, root, m_atomMotifClipHeader, &data, &target, &format, False)) {
     return false;
@@ -641,7 +641,7 @@ void XWindowsClipboard::motifFillCache()
   // get the Motif clipboard header property from the root window
   Atom target;
   SInt32 format;
-  String data;
+  std::string data;
   Window root = RootWindow(m_display, DefaultScreen(m_display));
   if (!XWindowsUtil::getWindowProperty(m_display, root, m_atomMotifClipHeader, &data, &target, &format, False)) {
     return;
@@ -680,13 +680,13 @@ void XWindowsClipboard::motifFillCache()
   auto formats = static_cast<const SInt32 *>(static_cast<const void *>(item.m_size + data.data()));
 
   // get the available formats
-  using MotifFormatMap = std::map<Atom, String>;
+  using MotifFormatMap = std::map<Atom, std::string>;
   MotifFormatMap motifFormats;
   for (SInt32 i = 0; i < numFormats; ++i) {
     // get Motif format property from the root window
     snprintf(name, buffer_size, "_MOTIF_CLIP_ITEM_%d", formats[i]);
     Atom atomFormat = XInternAtom(m_display, name, False);
-    String data;
+    std::string data;
     if (!XWindowsUtil::getWindowProperty(m_display, root, atomFormat, &data, &target, &format, False)) {
       continue;
     }
@@ -730,7 +730,7 @@ void XWindowsClipboard::motifFillCache()
 
     // get the data (finally)
     Atom actualTarget;
-    String targetData;
+    std::string targetData;
     if (!motifGetSelection(&motifFormat, &actualTarget, &targetData)) {
       LOG((CLOG_DEBUG1 "  no data for target %s", XWindowsUtil::atomToString(m_display, target).c_str()));
       continue;
@@ -744,7 +744,7 @@ void XWindowsClipboard::motifFillCache()
   }
 }
 
-bool XWindowsClipboard::motifGetSelection(const MotifClipFormat *format, Atom *actualTarget, String *data) const
+bool XWindowsClipboard::motifGetSelection(const MotifClipFormat *format, Atom *actualTarget, std::string *data) const
 {
   // if the current clipboard owner and the owner indicated by the
   // motif clip header are the same then transfer via a property on
@@ -776,7 +776,7 @@ bool XWindowsClipboard::insertMultipleReply(Window requestor, ::Time time, Atom
   // get the requested targets
   Atom target;
   SInt32 format;
-  String data;
+  std::string data;
   if (!XWindowsUtil::getWindowProperty(m_display, requestor, property, &data, &target, &format, False)) {
     // can't get the requested targets
     return false;
@@ -810,7 +810,7 @@ bool XWindowsClipboard::insertMultipleReply(Window requestor, ::Time time, Atom
   }
 
   // add reply for MULTIPLE request
-  insertReply(new Reply(requestor, m_atomMultiple, time, property, String(), None, 32));
+  insertReply(new Reply(requestor, m_atomMultiple, time, property, std::string(), None, 32));
 
   return true;
 }
@@ -1027,7 +1027,7 @@ bool XWindowsClipboard::sendReply(Reply *reply)
   LOG((CLOG_DEBUG2 "properties of 0x%08x:", reply->m_requestor));
   for (int i = 0; i < n; ++i) {
     Atom target;
-    String data;
+    std::string data;
     char *name = XGetAtomName(m_display, props[i]);
     if (!XWindowsUtil::getWindowProperty(m_display, reply->m_requestor, props[i], &data, &target, nullptr, False)) {
       LOG((CLOG_DEBUG2 "  %s: <can't read property>", name));
@@ -1035,8 +1035,8 @@ bool XWindowsClipboard::sendReply(Reply *reply)
       // convert to hex if contains non ascii symbols
       if (std::find_if(data.begin(), data.end(), [](const unsigned char &c) { return c < 32 || c > 126; }) !=
           data.end()) {
-        const String hex_digits = "0123456789abcdef";
-        String tmp;
+        const std::string hex_digits = "0123456789abcdef";
+        std::string tmp;
         tmp.reserve(data.length() * 3);
         std::for_each(data.begin(), data.end(), [hex_digits, &tmp](const unsigned char &c) {
           tmp += hex_digits[c >> 16];
@@ -1127,7 +1127,7 @@ bool XWindowsClipboard::wasOwnedAtTime(::Time time) const
   return (/*when >= 0 &&*/ when <= duration);
 }
 
-Atom XWindowsClipboard::getTargetsData(String &data, int *format) const
+Atom XWindowsClipboard::getTargetsData(std::string &data, int *format) const
 {
   assert(format != nullptr);
 
@@ -1150,7 +1150,7 @@ Atom XWindowsClipboard::getTargetsData(String &data, int *format) const
   return m_atomAtom;
 }
 
-Atom XWindowsClipboard::getTimestampData(String &data, int *format) const
+Atom XWindowsClipboard::getTimestampData(std::string &data, int *format) const
 {
   assert(format != nullptr);
 
@@ -1172,7 +1172,7 @@ XWindowsClipboard::CICCCMGetClipboard::CICCCMGetClipboard(Window requestor, Time
 }
 
 bool XWindowsClipboard::CICCCMGetClipboard::readClipboard(
-    Display *display, Atom selection, Atom target, Atom *actualTarget, String *data
+    Display *display, Atom selection, Atom target, Atom *actualTarget, std::string *data
 )
 {
   assert(actualTarget != nullptr);
@@ -1319,7 +1319,7 @@ bool XWindowsClipboard::CICCCMGetClipboard::processEvent(Display *display, XEven
 
   // get the data from the property
   Atom target;
-  const String::size_type oldSize = m_data->size();
+  const std::string::size_type oldSize = m_data->size();
   if (!XWindowsUtil::getWindowProperty(display, m_requestor, m_property, m_data, &target, nullptr, True)) {
     // unable to read property
     m_failed = true;
@@ -1397,7 +1397,7 @@ XWindowsClipboard::Reply::Reply(Window requestor, Atom target, ::Time time)
 }
 
 XWindowsClipboard::Reply::Reply(
-    Window requestor, Atom target, ::Time time, Atom property, const String &data, Atom type, int format
+    Window requestor, Atom target, ::Time time, Atom property, const std::string &data, Atom type, int format
 )
     : m_requestor(requestor),
       m_target(target),
diff --git a/src/lib/platform/XWindowsClipboard.h b/src/lib/platform/XWindowsClipboard.h
index 7dbb4b337..39a481f06 100644
--- a/src/lib/platform/XWindowsClipboard.h
+++ b/src/lib/platform/XWindowsClipboard.h
@@ -91,12 +91,12 @@ public:
 
   // IClipboard overrides
   virtual bool empty();
-  virtual void add(EFormat, const String &data);
+  virtual void add(EFormat, const std::string &data);
   virtual bool open(Time) const;
   virtual void close() const;
   virtual Time getTime() const;
   virtual bool has(EFormat) const;
-  virtual String get(EFormat) const;
+  virtual std::string get(EFormat) const;
 
 private:
   // remove all converters from our list
@@ -145,7 +145,7 @@ protected:
     // convert the given selection to the given type.  returns
     // true iff the conversion was successful or the conversion
     // cannot be performed (in which case *actualTarget == None).
-    bool readClipboard(Display *display, Atom selection, Atom target, Atom *actualTarget, String *data);
+    bool readClipboard(Display *display, Atom selection, Atom target, Atom *actualTarget, std::string *data);
 
   private:
     bool processEvent(Display *display, XEvent *event);
@@ -166,7 +166,7 @@ protected:
     bool m_reading = false;
 
     // the converted selection data
-    String *m_data = nullptr;
+    std::string *m_data = nullptr;
 
     // the actual type of the data.  if this is None then the
     // selection owner cannot convert to the requested type.
@@ -235,7 +235,7 @@ protected:
   {
   public:
     Reply(Window, Atom target, ::Time);
-    Reply(Window, Atom target, ::Time, Atom property, const String &data, Atom type, int format);
+    Reply(Window, Atom target, ::Time, Atom property, const std::string &data, Atom type, int format);
 
   public:
     // information about the request
@@ -251,7 +251,7 @@ protected:
     bool m_done;
 
     // the data to send and its type and format
-    String m_data;
+    std::string m_data;
     Atom m_type;
     int m_format;
 
@@ -264,7 +264,7 @@ protected:
 
   // ICCCM interoperability methods
   void icccmFillCache();
-  bool icccmGetSelection(Atom target, Atom *actualTarget, String *data) const;
+  bool icccmGetSelection(Atom target, Atom *actualTarget, std::string *data) const;
   Time icccmGetTime() const;
 
   // motif interoperability methods
@@ -272,7 +272,7 @@ protected:
   void motifUnlockClipboard() const;
   bool motifOwnsClipboard() const;
   void motifFillCache();
-  bool motifGetSelection(const MotifClipFormat *, Atom *actualTarget, String *data) const;
+  bool motifGetSelection(const MotifClipFormat *, Atom *actualTarget, std::string *data) const;
   Time motifGetTime() const;
 
   // reply methods
@@ -287,8 +287,8 @@ protected:
   bool wasOwnedAtTime(::Time) const;
 
   // data conversion methods
-  Atom getTargetsData(String &, int *format) const;
-  Atom getTimestampData(String &, int *format) const;
+  Atom getTargetsData(std::string &, int *format) const;
+  Atom getTimestampData(std::string &, int *format) const;
 
 private:
   using ConverterList = std::vector<IXWindowsClipboardConverter *>;
@@ -311,7 +311,7 @@ private:
   bool m_cached;
   Time m_cacheTime;
   bool m_added[kNumFormats];
-  String m_data[kNumFormats];
+  std::string m_data[kNumFormats];
 
   // conversion request replies
   ReplyMap m_replies;
@@ -373,14 +373,14 @@ public:
   getFormat().  The return data will be in the X selection
   format returned by getAtom().
   */
-  virtual String fromIClipboard(const String &) const = 0;
+  virtual std::string fromIClipboard(const std::string &) const = 0;
 
   //! Convert to IClipboard format
   /*!
   Convert from the X selection format to the IClipboard format
   (i.e., the reverse of fromIClipboard()).
   */
-  virtual String toIClipboard(const String &) const = 0;
+  virtual std::string toIClipboard(const std::string &) const = 0;
 
   //@}
 };
diff --git a/src/lib/platform/XWindowsClipboardAnyBitmapConverter.cpp b/src/lib/platform/XWindowsClipboardAnyBitmapConverter.cpp
index 0f527d612..f5a7506ab 100644
--- a/src/lib/platform/XWindowsClipboardAnyBitmapConverter.cpp
+++ b/src/lib/platform/XWindowsClipboardAnyBitmapConverter.cpp
@@ -105,7 +105,7 @@ int XWindowsClipboardAnyBitmapConverter::getDataSize() const
   return 8;
 }
 
-String XWindowsClipboardAnyBitmapConverter::fromIClipboard(const String &bmp) const
+std::string XWindowsClipboardAnyBitmapConverter::fromIClipboard(const std::string &bmp) const
 {
   // fill BMP info header with native-endian data
   CBMPInfoHeader infoHeader;
@@ -125,7 +125,7 @@ String XWindowsClipboardAnyBitmapConverter::fromIClipboard(const String &bmp) co
   // check that format is acceptable
   if (infoHeader.biSize != 40 || infoHeader.biWidth == 0 || infoHeader.biHeight == 0 || infoHeader.biPlanes != 0 ||
       infoHeader.biCompression != 0 || (infoHeader.biBitCount != 24 && infoHeader.biBitCount != 32)) {
-    return String();
+    return std::string();
   }
 
   // convert to image format
@@ -137,13 +137,13 @@ String XWindowsClipboardAnyBitmapConverter::fromIClipboard(const String &bmp) co
   }
 }
 
-String XWindowsClipboardAnyBitmapConverter::toIClipboard(const String &image) const
+std::string XWindowsClipboardAnyBitmapConverter::toIClipboard(const std::string &image) const
 {
   // convert to raw BMP data
   UInt32 w, h, depth;
-  String rawBMP = doToIClipboard(image, w, h, depth);
+  std::string rawBMP = doToIClipboard(image, w, h, depth);
   if (rawBMP.empty() || w == 0 || h == 0 || (depth != 24 && depth != 32)) {
-    return String();
+    return std::string();
   }
 
   // fill BMP info header with little-endian data
@@ -162,5 +162,5 @@ String XWindowsClipboardAnyBitmapConverter::toIClipboard(const String &image) co
   toLE(dst, static_cast<UInt32>(0));
 
   // construct image
-  return String(reinterpret_cast<const char *>(infoHeader), sizeof(infoHeader)) + rawBMP;
+  return std::string(reinterpret_cast<const char *>(infoHeader), sizeof(infoHeader)) + rawBMP;
 }
diff --git a/src/lib/platform/XWindowsClipboardAnyBitmapConverter.h b/src/lib/platform/XWindowsClipboardAnyBitmapConverter.h
index 0216ff2a1..d912254d2 100644
--- a/src/lib/platform/XWindowsClipboardAnyBitmapConverter.h
+++ b/src/lib/platform/XWindowsClipboardAnyBitmapConverter.h
@@ -31,26 +31,26 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const = 0;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 protected:
   //! Convert from IClipboard format
   /*!
   Convert raw BGR pixel data to another image format.
   */
-  virtual String doBGRFromIClipboard(const UInt8 *bgrData, UInt32 w, UInt32 h) const = 0;
+  virtual std::string doBGRFromIClipboard(const UInt8 *bgrData, UInt32 w, UInt32 h) const = 0;
 
   //! Convert from IClipboard format
   /*!
   Convert raw BGRA pixel data to another image format.
   */
-  virtual String doBGRAFromIClipboard(const UInt8 *bgrData, UInt32 w, UInt32 h) const = 0;
+  virtual std::string doBGRAFromIClipboard(const UInt8 *bgrData, UInt32 w, UInt32 h) const = 0;
 
   //! Convert to IClipboard format
   /*!
   Convert an image into raw BGR or BGRA image data and store the
   width, height, and image depth (24 or 32).
   */
-  virtual String doToIClipboard(const String &, UInt32 &w, UInt32 &h, UInt32 &depth) const = 0;
+  virtual std::string doToIClipboard(const std::string &, UInt32 &w, UInt32 &h, UInt32 &depth) const = 0;
 };
diff --git a/src/lib/platform/XWindowsClipboardBMPConverter.cpp b/src/lib/platform/XWindowsClipboardBMPConverter.cpp
index a8886752e..4abc4673b 100644
--- a/src/lib/platform/XWindowsClipboardBMPConverter.cpp
+++ b/src/lib/platform/XWindowsClipboardBMPConverter.cpp
@@ -88,7 +88,7 @@ int XWindowsClipboardBMPConverter::getDataSize() const
   return 8;
 }
 
-String XWindowsClipboardBMPConverter::fromIClipboard(const String &bmp) const
+std::string XWindowsClipboardBMPConverter::fromIClipboard(const std::string &bmp) const
 {
   // create BMP image
   UInt8 header[14];
@@ -99,20 +99,20 @@ String XWindowsClipboardBMPConverter::fromIClipboard(const String &bmp) const
   toLE(dst, static_cast<UInt16>(0));
   toLE(dst, static_cast<UInt16>(0));
   toLE(dst, static_cast<UInt32>(14 + 40));
-  return String(reinterpret_cast<const char *>(header), 14) + bmp;
+  return std::string(reinterpret_cast<const char *>(header), 14) + bmp;
 }
 
-String XWindowsClipboardBMPConverter::toIClipboard(const String &bmp) const
+std::string XWindowsClipboardBMPConverter::toIClipboard(const std::string &bmp) const
 {
   // make sure data is big enough for a BMP file
   if (bmp.size() <= 14 + 40) {
-    return String();
+    return std::string();
   }
 
   // check BMP file header
   const UInt8 *rawBMPHeader = reinterpret_cast<const UInt8 *>(bmp.data());
   if (rawBMPHeader[0] != 'B' || rawBMPHeader[1] != 'M') {
-    return String();
+    return std::string();
   }
 
   // get offset to image data
diff --git a/src/lib/platform/XWindowsClipboardBMPConverter.h b/src/lib/platform/XWindowsClipboardBMPConverter.h
index ba7d913b8..69eab3f88 100644
--- a/src/lib/platform/XWindowsClipboardBMPConverter.h
+++ b/src/lib/platform/XWindowsClipboardBMPConverter.h
@@ -31,8 +31,8 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 private:
   Atom m_atom;
diff --git a/src/lib/platform/XWindowsClipboardHTMLConverter.cpp b/src/lib/platform/XWindowsClipboardHTMLConverter.cpp
index 2a7b6e3e8..3d84da384 100644
--- a/src/lib/platform/XWindowsClipboardHTMLConverter.cpp
+++ b/src/lib/platform/XWindowsClipboardHTMLConverter.cpp
@@ -50,12 +50,12 @@ int XWindowsClipboardHTMLConverter::getDataSize() const
   return 8;
 }
 
-String XWindowsClipboardHTMLConverter::fromIClipboard(const String &data) const
+std::string XWindowsClipboardHTMLConverter::fromIClipboard(const std::string &data) const
 {
   return data;
 }
 
-String XWindowsClipboardHTMLConverter::toIClipboard(const String &data) const
+std::string XWindowsClipboardHTMLConverter::toIClipboard(const std::string &data) const
 {
   if (Unicode::isUTF8(data)) {
     return data;
diff --git a/src/lib/platform/XWindowsClipboardHTMLConverter.h b/src/lib/platform/XWindowsClipboardHTMLConverter.h
index add6ec7ea..779af4784 100644
--- a/src/lib/platform/XWindowsClipboardHTMLConverter.h
+++ b/src/lib/platform/XWindowsClipboardHTMLConverter.h
@@ -34,8 +34,8 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 private:
   Atom m_atom;
diff --git a/src/lib/platform/XWindowsClipboardTextConverter.cpp b/src/lib/platform/XWindowsClipboardTextConverter.cpp
index 066becf34..a0d9d522c 100644
--- a/src/lib/platform/XWindowsClipboardTextConverter.cpp
+++ b/src/lib/platform/XWindowsClipboardTextConverter.cpp
@@ -50,16 +50,16 @@ int XWindowsClipboardTextConverter::getDataSize() const
   return 8;
 }
 
-String XWindowsClipboardTextConverter::fromIClipboard(const String &data) const
+std::string XWindowsClipboardTextConverter::fromIClipboard(const std::string &data) const
 {
   return Unicode::UTF8ToText(data);
 }
 
-String XWindowsClipboardTextConverter::toIClipboard(const String &data) const
+std::string XWindowsClipboardTextConverter::toIClipboard(const std::string &data) const
 {
   // convert to UTF-8
   bool errors;
-  String utf8 = Unicode::textToUTF8(data, &errors);
+  std::string utf8 = Unicode::textToUTF8(data, &errors);
 
   // if there were decoding errors then, to support old applications
   // that don't understand UTF-8 but can report the exact binary
diff --git a/src/lib/platform/XWindowsClipboardTextConverter.h b/src/lib/platform/XWindowsClipboardTextConverter.h
index ad7097838..2030384bb 100644
--- a/src/lib/platform/XWindowsClipboardTextConverter.h
+++ b/src/lib/platform/XWindowsClipboardTextConverter.h
@@ -34,8 +34,8 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 private:
   Atom m_atom;
diff --git a/src/lib/platform/XWindowsClipboardUCS2Converter.cpp b/src/lib/platform/XWindowsClipboardUCS2Converter.cpp
index 3c2317ba4..a6037c74b 100644
--- a/src/lib/platform/XWindowsClipboardUCS2Converter.cpp
+++ b/src/lib/platform/XWindowsClipboardUCS2Converter.cpp
@@ -50,12 +50,12 @@ int XWindowsClipboardUCS2Converter::getDataSize() const
   return 16;
 }
 
-String XWindowsClipboardUCS2Converter::fromIClipboard(const String &data) const
+std::string XWindowsClipboardUCS2Converter::fromIClipboard(const std::string &data) const
 {
   return Unicode::UTF8ToUCS2(data);
 }
 
-String XWindowsClipboardUCS2Converter::toIClipboard(const String &data) const
+std::string XWindowsClipboardUCS2Converter::toIClipboard(const std::string &data) const
 {
   return Unicode::UCS2ToUTF8(data);
 }
diff --git a/src/lib/platform/XWindowsClipboardUCS2Converter.h b/src/lib/platform/XWindowsClipboardUCS2Converter.h
index 7115d48e8..46146174f 100644
--- a/src/lib/platform/XWindowsClipboardUCS2Converter.h
+++ b/src/lib/platform/XWindowsClipboardUCS2Converter.h
@@ -34,8 +34,8 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 private:
   Atom m_atom;
diff --git a/src/lib/platform/XWindowsClipboardUTF8Converter.cpp b/src/lib/platform/XWindowsClipboardUTF8Converter.cpp
index fcf7287b8..4b9094b62 100644
--- a/src/lib/platform/XWindowsClipboardUTF8Converter.cpp
+++ b/src/lib/platform/XWindowsClipboardUTF8Converter.cpp
@@ -56,12 +56,12 @@ static bool isCR(char ch)
   return (ch == '\r');
 }
 
-String XWindowsClipboardUTF8Converter::fromIClipboard(const String &data) const
+std::string XWindowsClipboardUTF8Converter::fromIClipboard(const std::string &data) const
 {
   return data;
 }
 
-String XWindowsClipboardUTF8Converter::toIClipboard(const String &data) const
+std::string XWindowsClipboardUTF8Converter::toIClipboard(const std::string &data) const
 {
   // https://bugzilla.mozilla.org/show_bug.cgi?id=1547595
   // GTK normalizes the clipboard's line endings to CRLF (\r\n) internally.
@@ -74,7 +74,7 @@ String XWindowsClipboardUTF8Converter::toIClipboard(const String &data) const
   // When normalize clipboard is set, any \r present in the string is removed
 
   if (m_normalize) {
-    String copy = data;
+    std::string copy = data;
 
     copy.erase(std::remove_if(copy.begin(), copy.end(), isCR), copy.end());
     return copy;
diff --git a/src/lib/platform/XWindowsClipboardUTF8Converter.h b/src/lib/platform/XWindowsClipboardUTF8Converter.h
index af7dc9509..c4d7ecb6b 100644
--- a/src/lib/platform/XWindowsClipboardUTF8Converter.h
+++ b/src/lib/platform/XWindowsClipboardUTF8Converter.h
@@ -34,8 +34,8 @@ public:
   virtual IClipboard::EFormat getFormat() const;
   virtual Atom getAtom() const;
   virtual int getDataSize() const;
-  virtual String fromIClipboard(const String &) const;
-  virtual String toIClipboard(const String &) const;
+  virtual std::string fromIClipboard(const std::string &) const;
+  virtual std::string toIClipboard(const std::string &) const;
 
 private:
   Atom m_atom;
diff --git a/src/lib/platform/XWindowsKeyState.cpp b/src/lib/platform/XWindowsKeyState.cpp
index a8da7e428..bc336e646 100644
--- a/src/lib/platform/XWindowsKeyState.cpp
+++ b/src/lib/platform/XWindowsKeyState.cpp
@@ -26,7 +26,6 @@
 #include "platform/XWindowsKeyState.h"
 
 #include "base/Log.h"
-#include "base/String.h"
 #include "common/stdmap.h"
 #include "deskflow/AppUtil.h"
 #include "deskflow/ClientApp.h"
diff --git a/src/lib/platform/XWindowsScreen.cpp b/src/lib/platform/XWindowsScreen.cpp
index c41105f1b..11f35130f 100644
--- a/src/lib/platform/XWindowsScreen.cpp
+++ b/src/lib/platform/XWindowsScreen.cpp
@@ -23,7 +23,6 @@
 #include "base/IEventQueue.h"
 #include "base/Log.h"
 #include "base/Stopwatch.h"
-#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "deskflow/App.h"
 #include "deskflow/ArgsBase.h"
@@ -472,7 +471,7 @@ bool XWindowsScreen::isPrimary() const
   return m_isPrimary;
 }
 
-String XWindowsScreen::getSecureInputApp() const
+std::string XWindowsScreen::getSecureInputApp() const
 {
   // ignore on Linux
   return "";
diff --git a/src/lib/platform/XWindowsScreen.h b/src/lib/platform/XWindowsScreen.h
index a7f2c5348..8a4ca245c 100644
--- a/src/lib/platform/XWindowsScreen.h
+++ b/src/lib/platform/XWindowsScreen.h
@@ -89,7 +89,7 @@ public:
   void setOptions(const OptionsList &options) override;
   void setSequenceNumber(UInt32) override;
   bool isPrimary() const override;
-  String getSecureInputApp() const override;
+  std::string getSecureInputApp() const override;
 
 protected:
   // IPlatformScreen overrides
diff --git a/src/lib/platform/XWindowsUtil.cpp b/src/lib/platform/XWindowsUtil.cpp
index f5226c702..1093544aa 100644
--- a/src/lib/platform/XWindowsUtil.cpp
+++ b/src/lib/platform/XWindowsUtil.cpp
@@ -1515,7 +1515,7 @@ static const KeySym s_map1008FF[] = {
 XWindowsUtil::KeySymMap XWindowsUtil::s_keySymToUCS4;
 
 bool XWindowsUtil::getWindowProperty(
-    Display *display, Window window, Atom property, String *data, Atom *type, SInt32 *format, bool deleteProperty
+    Display *display, Window window, Atom property, std::string *data, Atom *type, SInt32 *format, bool deleteProperty
 )
 {
   assert(display != NULL);
@@ -1816,7 +1816,7 @@ UInt32 XWindowsUtil::getModifierBitForKeySym(KeySym keysym)
   }
 }
 
-String XWindowsUtil::atomToString(Display *display, Atom atom)
+std::string XWindowsUtil::atomToString(Display *display, Atom atom)
 {
   if (atom == 0) {
     return "None";
@@ -1828,19 +1828,19 @@ String XWindowsUtil::atomToString(Display *display, Atom atom)
   if (error) {
     return deskflow::string::sprintf("<UNKNOWN> (%d)", (int)atom);
   } else {
-    String msg = deskflow::string::sprintf("%s (%d)", name, (int)atom);
+    std::string msg = deskflow::string::sprintf("%s (%d)", name, (int)atom);
     XFree(name);
     return msg;
   }
 }
 
-String XWindowsUtil::atomsToString(Display *display, const Atom *atom, UInt32 num)
+std::string XWindowsUtil::atomsToString(Display *display, const Atom *atom, UInt32 num)
 {
   char **names = new char *[num];
   bool error = false;
   XWindowsUtil::ErrorLock lock(display, &error);
   XGetAtomNames(display, const_cast<Atom *>(atom), (int)num, names);
-  String msg;
+  std::string msg;
   if (error) {
     for (UInt32 i = 0; i < num; ++i) {
       msg += deskflow::string::sprintf("<UNKNOWN> (%d), ", (int)atom[i]);
@@ -1858,7 +1858,7 @@ String XWindowsUtil::atomsToString(Display *display, const Atom *atom, UInt32 nu
   return msg;
 }
 
-void XWindowsUtil::convertAtomProperty(String &data)
+void XWindowsUtil::convertAtomProperty(std::string &data)
 {
   // as best i can tell, 64-bit systems don't pack Atoms into properties
   // as 32-bit numbers but rather as the 64-bit numbers they are.  that
@@ -1872,17 +1872,17 @@ void XWindowsUtil::convertAtomProperty(String &data)
   }
 }
 
-void XWindowsUtil::appendAtomData(String &data, Atom atom)
+void XWindowsUtil::appendAtomData(std::string &data, Atom atom)
 {
   data.append(reinterpret_cast<char *>(&atom), sizeof(Atom));
 }
 
-void XWindowsUtil::replaceAtomData(String &data, UInt32 index, Atom atom)
+void XWindowsUtil::replaceAtomData(std::string &data, UInt32 index, Atom atom)
 {
   data.replace(index * sizeof(Atom), sizeof(Atom), reinterpret_cast<const char *>(&atom), sizeof(Atom));
 }
 
-void XWindowsUtil::appendTimeData(String &data, Time time)
+void XWindowsUtil::appendTimeData(std::string &data, Time time)
 {
   data.append(reinterpret_cast<char *>(&time), sizeof(Time));
 }
diff --git a/src/lib/platform/XWindowsUtil.h b/src/lib/platform/XWindowsUtil.h
index 0631041b0..a809ce1f8 100644
--- a/src/lib/platform/XWindowsUtil.h
+++ b/src/lib/platform/XWindowsUtil.h
@@ -19,10 +19,11 @@
 #pragma once
 
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "common/stdmap.h"
 #include "common/stdvector.h"
 
+#include <string>
+
 #if X_DISPLAY_MISSING
 #error X11 is required to build deskflow
 #else
@@ -44,7 +45,7 @@ public:
   property is deleted after being read.
   */
   static bool getWindowProperty(
-      Display *, Window window, Atom property, String *data, Atom *type, SInt32 *format, bool deleteProperty
+      Display *, Window window, Atom property, std::string *data, Atom *type, SInt32 *format, bool deleteProperty
   );
 
   //! Set property
@@ -79,42 +80,42 @@ public:
   /*!
   Converts \p atom to its string representation.
   */
-  static String atomToString(Display *, Atom atom);
+  static std::string atomToString(Display *, Atom atom);
 
   //! Convert several Atoms to a string
   /*!
   Converts each atom in \p atoms to its string representation and
   concatenates the results.
   */
-  static String atomsToString(Display *display, const Atom *atom, UInt32 num);
+  static std::string atomsToString(Display *display, const Atom *atom, UInt32 num);
 
   //! Prepare a property of atoms for use
   /*!
   64-bit systems may need to modify a property's data if it's a
   list of Atoms before using it.
   */
-  static void convertAtomProperty(String &data);
+  static void convertAtomProperty(std::string &data);
 
   //! Append an Atom to property data
   /*!
   Converts \p atom to a 32-bit on-the-wire format and appends it to
   \p data.
   */
-  static void appendAtomData(String &data, Atom atom);
+  static void appendAtomData(std::string &data, Atom atom);
 
   //! Replace an Atom in property data
   /*!
   Converts \p atom to a 32-bit on-the-wire format and replaces the atom
   at index \p index in \p data.
   */
-  static void replaceAtomData(String &data, UInt32 index, Atom atom);
+  static void replaceAtomData(std::string &data, UInt32 index, Atom atom);
 
   //! Append an Time to property data
   /*!
   Converts \p time to a 32-bit on-the-wire format and appends it to
   \p data.
   */
-  static void appendTimeData(String &data, Time time);
+  static void appendTimeData(std::string &data, Time time);
 
   //! X11 error handler
   /*!
diff --git a/src/lib/server/BaseClientProxy.cpp b/src/lib/server/BaseClientProxy.cpp
index 434403574..1e15081c4 100644
--- a/src/lib/server/BaseClientProxy.cpp
+++ b/src/lib/server/BaseClientProxy.cpp
@@ -22,7 +22,7 @@
 // BaseClientProxy
 //
 
-BaseClientProxy::BaseClientProxy(const String &name) : m_name(name), m_x(0), m_y(0)
+BaseClientProxy::BaseClientProxy(const std::string &name) : m_name(name), m_x(0), m_y(0)
 {
   // do nothing
 }
@@ -44,7 +44,7 @@ void BaseClientProxy::getJumpCursorPos(SInt32 &x, SInt32 &y) const
   y = m_y;
 }
 
-String BaseClientProxy::getName() const
+std::string BaseClientProxy::getName() const
 {
   return m_name;
 }
diff --git a/src/lib/server/BaseClientProxy.h b/src/lib/server/BaseClientProxy.h
index fbbfe75bc..173ac09fa 100644
--- a/src/lib/server/BaseClientProxy.h
+++ b/src/lib/server/BaseClientProxy.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "deskflow/IClient.h"
 
 namespace deskflow {
@@ -32,7 +31,7 @@ public:
   /*!
   \c name is the name of the client.
   */
-  BaseClientProxy(const String &name);
+  BaseClientProxy(const std::string &name);
   ~BaseClientProxy();
 
   //! @name manipulators
@@ -77,8 +76,8 @@ public:
   virtual void setClipboard(ClipboardID, const IClipboard *) = 0;
   virtual void grabClipboard(ClipboardID) = 0;
   virtual void setClipboardDirty(ClipboardID, bool) = 0;
-  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const String &) = 0;
-  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &lang) = 0;
+  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &) = 0;
+  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &lang) = 0;
   virtual void keyUp(KeyID, KeyModifierMask, KeyButton) = 0;
   virtual void mouseDown(ButtonID) = 0;
   virtual void mouseUp(ButtonID) = 0;
@@ -90,12 +89,12 @@ public:
   virtual void setOptions(const OptionsList &options) = 0;
   virtual void sendDragInfo(UInt32 fileCount, const char *info, size_t size) = 0;
   virtual void fileChunkSending(UInt8 mark, char *data, size_t dataSize) = 0;
-  virtual String getSecureInputApp() const = 0;
-  virtual void secureInputNotification(const String &app) const = 0;
-  virtual String getName() const;
+  virtual std::string getSecureInputApp() const = 0;
+  virtual void secureInputNotification(const std::string &app) const = 0;
+  virtual std::string getName() const;
   virtual deskflow::IStream *getStream() const = 0;
 
 private:
-  String m_name;
+  std::string m_name;
   SInt32 m_x, m_y;
 };
diff --git a/src/lib/server/ClientProxy.cpp b/src/lib/server/ClientProxy.cpp
index 6848ee185..eabf6659e 100644
--- a/src/lib/server/ClientProxy.cpp
+++ b/src/lib/server/ClientProxy.cpp
@@ -27,7 +27,7 @@
 // ClientProxy
 //
 
-ClientProxy::ClientProxy(const String &name, deskflow::IStream *stream) : BaseClientProxy(name), m_stream(stream)
+ClientProxy::ClientProxy(const std::string &name, deskflow::IStream *stream) : BaseClientProxy(name), m_stream(stream)
 {
 }
 
diff --git a/src/lib/server/ClientProxy.h b/src/lib/server/ClientProxy.h
index fca45008d..bcc8706e2 100644
--- a/src/lib/server/ClientProxy.h
+++ b/src/lib/server/ClientProxy.h
@@ -20,7 +20,6 @@
 
 #include "base/Event.h"
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "server/BaseClientProxy.h"
 
 namespace deskflow {
@@ -34,7 +33,7 @@ public:
   /*!
   \c name is the name of the client.
   */
-  ClientProxy(const String &name, deskflow::IStream *adoptedStream);
+  ClientProxy(const std::string &name, deskflow::IStream *adoptedStream);
   ClientProxy(ClientProxy const &) = delete;
   ClientProxy(ClientProxy &&) = delete;
   ~ClientProxy();
@@ -75,8 +74,8 @@ public:
   void setClipboard(ClipboardID, const IClipboard *) override = 0;
   void grabClipboard(ClipboardID) override = 0;
   void setClipboardDirty(ClipboardID, bool) override = 0;
-  void keyDown(KeyID, KeyModifierMask, KeyButton, const String &) override = 0;
-  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &lang) override = 0;
+  void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &) override = 0;
+  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &lang) override = 0;
   void keyUp(KeyID, KeyModifierMask, KeyButton) override = 0;
   void mouseDown(ButtonID) override = 0;
   void mouseUp(ButtonID) override = 0;
@@ -88,7 +87,7 @@ public:
   void setOptions(const OptionsList &options) override = 0;
   void sendDragInfo(UInt32 fileCount, const char *info, size_t size) override = 0;
   void fileChunkSending(UInt8 mark, char *data, size_t dataSize) override = 0;
-  void secureInputNotification(const String &app) const override = 0;
+  void secureInputNotification(const std::string &app) const override = 0;
 
 private:
   deskflow::IStream *m_stream;
diff --git a/src/lib/server/ClientProxy1_0.cpp b/src/lib/server/ClientProxy1_0.cpp
index 02f0e98b4..dc7dc8408 100644
--- a/src/lib/server/ClientProxy1_0.cpp
+++ b/src/lib/server/ClientProxy1_0.cpp
@@ -31,7 +31,7 @@
 // ClientProxy1_0
 //
 
-ClientProxy1_0::ClientProxy1_0(const String &name, deskflow::IStream *stream, IEventQueue *events)
+ClientProxy1_0::ClientProxy1_0(const std::string &name, deskflow::IStream *stream, IEventQueue *events)
     : ClientProxy(name, stream),
       m_heartbeatTimer(NULL),
       m_parser(&ClientProxy1_0::parseHandshakeMessage),
@@ -278,13 +278,13 @@ void ClientProxy1_0::setClipboardDirty(ClipboardID id, bool dirty)
   m_clipboard[id].m_dirty = dirty;
 }
 
-void ClientProxy1_0::keyDown(KeyID key, KeyModifierMask mask, KeyButton, const String &)
+void ClientProxy1_0::keyDown(KeyID key, KeyModifierMask mask, KeyButton, const std::string &)
 {
   LOG((CLOG_DEBUG1 "send key down to \"%s\" id=%d, mask=0x%04x", getName().c_str(), key, mask));
   ProtocolUtil::writef(getStream(), kMsgDKeyDown1_0, key, mask);
 }
 
-void ClientProxy1_0::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton, const String &)
+void ClientProxy1_0::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton, const std::string &)
 {
   LOG((CLOG_DEBUG1 "send key repeat to \"%s\" id=%d, mask=0x%04x, count=%d", getName().c_str(), key, mask, count));
   ProtocolUtil::writef(getStream(), kMsgDKeyRepeat1_0, key, mask, count);
@@ -338,14 +338,14 @@ void ClientProxy1_0::fileChunkSending(UInt8 mark, char *data, size_t dataSize)
   LOG((CLOG_DEBUG "fileChunkSending not supported"));
 }
 
-String ClientProxy1_0::getSecureInputApp() const
+std::string ClientProxy1_0::getSecureInputApp() const
 {
   // ignore -- not supported on clients
   LOG((CLOG_DEBUG "getSecureInputApp not supported"));
   return "";
 }
 
-void ClientProxy1_0::secureInputNotification(const String &app) const
+void ClientProxy1_0::secureInputNotification(const std::string &app) const
 {
   // ignore -- not supported in protocol 1.0
   LOG((CLOG_DEBUG "secureInputNotification not supported"));
diff --git a/src/lib/server/ClientProxy1_0.h b/src/lib/server/ClientProxy1_0.h
index 0339b44e6..f86e11837 100644
--- a/src/lib/server/ClientProxy1_0.h
+++ b/src/lib/server/ClientProxy1_0.h
@@ -30,7 +30,7 @@ class IEventQueue;
 class ClientProxy1_0 : public ClientProxy
 {
 public:
-  ClientProxy1_0(const String &name, deskflow::IStream *adoptedStream, IEventQueue *events);
+  ClientProxy1_0(const std::string &name, deskflow::IStream *adoptedStream, IEventQueue *events);
   ClientProxy1_0(ClientProxy1_0 const &) = delete;
   ClientProxy1_0(ClientProxy1_0 &&) = delete;
   ~ClientProxy1_0();
@@ -49,8 +49,8 @@ public:
   void setClipboard(ClipboardID, const IClipboard *) override;
   void grabClipboard(ClipboardID) override;
   void setClipboardDirty(ClipboardID, bool) override;
-  void keyDown(KeyID, KeyModifierMask, KeyButton, const String &) override;
-  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &) override;
+  void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &) override;
+  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &) override;
   void keyUp(KeyID, KeyModifierMask, KeyButton) override;
   void mouseDown(ButtonID) override;
   void mouseUp(ButtonID) override;
@@ -62,8 +62,8 @@ public:
   void setOptions(const OptionsList &options) override;
   void sendDragInfo(UInt32 fileCount, const char *info, size_t size) override;
   void fileChunkSending(UInt8 mark, char *data, size_t dataSize) override;
-  String getSecureInputApp() const override;
-  void secureInputNotification(const String &app) const override;
+  std::string getSecureInputApp() const override;
+  void secureInputNotification(const std::string &app) const override;
 
 protected:
   virtual bool parseHandshakeMessage(const UInt8 *code);
diff --git a/src/lib/server/ClientProxy1_1.cpp b/src/lib/server/ClientProxy1_1.cpp
index 16c71ec02..5ee633340 100644
--- a/src/lib/server/ClientProxy1_1.cpp
+++ b/src/lib/server/ClientProxy1_1.cpp
@@ -28,7 +28,7 @@
 // ClientProxy1_1
 //
 
-ClientProxy1_1::ClientProxy1_1(const String &name, deskflow::IStream *stream, IEventQueue *events)
+ClientProxy1_1::ClientProxy1_1(const std::string &name, deskflow::IStream *stream, IEventQueue *events)
     : ClientProxy1_0(name, stream, events)
 {
   // do nothing
@@ -39,13 +39,13 @@ ClientProxy1_1::~ClientProxy1_1()
   // do nothing
 }
 
-void ClientProxy1_1::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const String &)
+void ClientProxy1_1::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const std::string &)
 {
   LOG((CLOG_DEBUG1 "send key down to \"%s\" id=%d, mask=0x%04x, button=0x%04x", getName().c_str(), key, mask, button));
   ProtocolUtil::writef(getStream(), kMsgDKeyDown, key, mask, button);
 }
 
-void ClientProxy1_1::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+void ClientProxy1_1::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang)
 {
   LOG(
       (CLOG_DEBUG1 "send key repeat to \"%s\" id=%d, mask=0x%04x, count=%d, "
diff --git a/src/lib/server/ClientProxy1_1.h b/src/lib/server/ClientProxy1_1.h
index 0f22bb3c0..88133e216 100644
--- a/src/lib/server/ClientProxy1_1.h
+++ b/src/lib/server/ClientProxy1_1.h
@@ -24,11 +24,11 @@
 class ClientProxy1_1 : public ClientProxy1_0
 {
 public:
-  ClientProxy1_1(const String &name, deskflow::IStream *adoptedStream, IEventQueue *events);
+  ClientProxy1_1(const std::string &name, deskflow::IStream *adoptedStream, IEventQueue *events);
   ~ClientProxy1_1();
 
   // IClient overrides
-  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const String &);
-  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &);
+  virtual void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &);
+  virtual void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &);
   virtual void keyUp(KeyID, KeyModifierMask, KeyButton);
 };
diff --git a/src/lib/server/ClientProxy1_2.cpp b/src/lib/server/ClientProxy1_2.cpp
index 7d65d9ed6..7c6e8565f 100644
--- a/src/lib/server/ClientProxy1_2.cpp
+++ b/src/lib/server/ClientProxy1_2.cpp
@@ -25,7 +25,7 @@
 // ClientProxy1_1
 //
 
-ClientProxy1_2::ClientProxy1_2(const String &name, deskflow::IStream *stream, IEventQueue *events)
+ClientProxy1_2::ClientProxy1_2(const std::string &name, deskflow::IStream *stream, IEventQueue *events)
     : ClientProxy1_1(name, stream, events)
 {
   // do nothing
diff --git a/src/lib/server/ClientProxy1_2.h b/src/lib/server/ClientProxy1_2.h
index 5ebd73a3a..db75515a0 100644
--- a/src/lib/server/ClientProxy1_2.h
+++ b/src/lib/server/ClientProxy1_2.h
@@ -26,7 +26,7 @@ class IEventQueue;
 class ClientProxy1_2 : public ClientProxy1_1
 {
 public:
-  ClientProxy1_2(const String &name, deskflow::IStream *adoptedStream, IEventQueue *events);
+  ClientProxy1_2(const std::string &name, deskflow::IStream *adoptedStream, IEventQueue *events);
   ~ClientProxy1_2();
 
   // IClient overrides
diff --git a/src/lib/server/ClientProxy1_3.cpp b/src/lib/server/ClientProxy1_3.cpp
index e52ab6d81..e8da23bcb 100644
--- a/src/lib/server/ClientProxy1_3.cpp
+++ b/src/lib/server/ClientProxy1_3.cpp
@@ -30,7 +30,7 @@
 // ClientProxy1_3
 //
 
-ClientProxy1_3::ClientProxy1_3(const String &name, deskflow::IStream *stream, IEventQueue *events)
+ClientProxy1_3::ClientProxy1_3(const std::string &name, deskflow::IStream *stream, IEventQueue *events)
     : ClientProxy1_2(name, stream, events),
       m_keepAliveRate(kKeepAliveRate),
       m_keepAliveTimer(NULL),
diff --git a/src/lib/server/ClientProxy1_3.h b/src/lib/server/ClientProxy1_3.h
index 118d06d4c..cefb1e461 100644
--- a/src/lib/server/ClientProxy1_3.h
+++ b/src/lib/server/ClientProxy1_3.h
@@ -24,7 +24,7 @@
 class ClientProxy1_3 : public ClientProxy1_2
 {
 public:
-  ClientProxy1_3(const String &name, deskflow::IStream *adoptedStream, IEventQueue *events);
+  ClientProxy1_3(const std::string &name, deskflow::IStream *adoptedStream, IEventQueue *events);
   ClientProxy1_3(ClientProxy1_3 const &) = delete;
   ClientProxy1_3(ClientProxy1_3 &&) = delete;
   ~ClientProxy1_3();
diff --git a/src/lib/server/ClientProxy1_4.cpp b/src/lib/server/ClientProxy1_4.cpp
index e6fefef1f..d7bc17264 100644
--- a/src/lib/server/ClientProxy1_4.cpp
+++ b/src/lib/server/ClientProxy1_4.cpp
@@ -31,7 +31,7 @@
 // ClientProxy1_4
 //
 
-ClientProxy1_4::ClientProxy1_4(const String &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
+ClientProxy1_4::ClientProxy1_4(const std::string &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
     : ClientProxy1_3(name, stream, events),
       m_server(server)
 {
@@ -42,12 +42,12 @@ ClientProxy1_4::~ClientProxy1_4()
 {
 }
 
-void ClientProxy1_4::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const String &lang)
+void ClientProxy1_4::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const std::string &lang)
 {
   ClientProxy1_3::keyDown(key, mask, button, lang);
 }
 
-void ClientProxy1_4::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+void ClientProxy1_4::keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang)
 {
   ClientProxy1_3::keyRepeat(key, mask, count, button, lang);
 }
diff --git a/src/lib/server/ClientProxy1_4.h b/src/lib/server/ClientProxy1_4.h
index 21e9ced4a..25944717d 100644
--- a/src/lib/server/ClientProxy1_4.h
+++ b/src/lib/server/ClientProxy1_4.h
@@ -26,7 +26,7 @@ class Server;
 class ClientProxy1_4 : public ClientProxy1_3
 {
 public:
-  ClientProxy1_4(const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
+  ClientProxy1_4(const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
   ~ClientProxy1_4();
 
   //! @name accessors
@@ -41,8 +41,8 @@ public:
   //@}
 
   // IClient overrides
-  virtual void keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const String &);
-  virtual void keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang);
+  virtual void keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const std::string &);
+  virtual void keyRepeat(KeyID key, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang);
   virtual void keyUp(KeyID key, KeyModifierMask mask, KeyButton button);
   virtual void keepAlive();
 
diff --git a/src/lib/server/ClientProxy1_5.cpp b/src/lib/server/ClientProxy1_5.cpp
index ab470a3d5..9bf067982 100644
--- a/src/lib/server/ClientProxy1_5.cpp
+++ b/src/lib/server/ClientProxy1_5.cpp
@@ -31,7 +31,7 @@
 // ClientProxy1_5
 //
 
-ClientProxy1_5::ClientProxy1_5(const String &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
+ClientProxy1_5::ClientProxy1_5(const std::string &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
     : ClientProxy1_4(name, stream, server, events),
       m_events(events)
 {
@@ -49,7 +49,7 @@ ClientProxy1_5::~ClientProxy1_5()
 
 void ClientProxy1_5::sendDragInfo(UInt32 fileCount, const char *info, size_t size)
 {
-  String data(info, size);
+  std::string data(info, size);
 
   ProtocolUtil::writef(getStream(), kMsgDDragInfo, fileCount, &data);
 }
@@ -81,7 +81,7 @@ void ClientProxy1_5::fileChunkReceived()
     m_events->addEvent(Event(m_events->forFile().fileRecieveCompleted(), server));
   } else if (result == kStart) {
     if (server->getFakeDragFileList().size() > 0) {
-      String filename = server->getFakeDragFileList().at(0).getFilename();
+      std::string filename = server->getFakeDragFileList().at(0).getFilename();
       LOG((CLOG_DEBUG "start receiving %s", filename.c_str()));
     }
   }
@@ -91,7 +91,7 @@ void ClientProxy1_5::dragInfoReceived()
 {
   // parse
   UInt32 fileNum = 0;
-  String content;
+  std::string content;
   ProtocolUtil::readf(getStream(), kMsgDDragInfo + 4, &fileNum, &content);
 
   m_server->dragInfoReceived(fileNum, content);
diff --git a/src/lib/server/ClientProxy1_5.h b/src/lib/server/ClientProxy1_5.h
index 74d07dce5..d7bfd19ff 100644
--- a/src/lib/server/ClientProxy1_5.h
+++ b/src/lib/server/ClientProxy1_5.h
@@ -28,7 +28,7 @@ class IEventQueue;
 class ClientProxy1_5 : public ClientProxy1_4
 {
 public:
-  ClientProxy1_5(const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
+  ClientProxy1_5(const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
   ClientProxy1_5(ClientProxy1_5 const &) = delete;
   ClientProxy1_5(ClientProxy1_5 &&) = delete;
   ~ClientProxy1_5();
diff --git a/src/lib/server/ClientProxy1_6.cpp b/src/lib/server/ClientProxy1_6.cpp
index 289757657..3031b613e 100644
--- a/src/lib/server/ClientProxy1_6.cpp
+++ b/src/lib/server/ClientProxy1_6.cpp
@@ -29,7 +29,7 @@
 // ClientProxy1_6
 //
 
-ClientProxy1_6::ClientProxy1_6(const String &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
+ClientProxy1_6::ClientProxy1_6(const std::string &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
     : ClientProxy1_5(name, stream, server, events),
       m_events(events)
 {
@@ -51,7 +51,7 @@ void ClientProxy1_6::setClipboard(ClipboardID id, const IClipboard *clipboard)
     m_clipboard[id].m_dirty = false;
     Clipboard::copy(&m_clipboard[id].m_clipboard, clipboard);
 
-    String data = m_clipboard[id].m_clipboard.marshall();
+    std::string data = m_clipboard[id].m_clipboard.marshall();
 
     size_t size = data.size();
     LOG((CLOG_DEBUG "sending clipboard %d to \"%s\"", id, getName().c_str()));
@@ -68,7 +68,7 @@ void ClientProxy1_6::handleClipboardSendingEvent(const Event &event, void *)
 bool ClientProxy1_6::recvClipboard()
 {
   // parse message
-  static String dataCached;
+  static std::string dataCached;
   ClipboardID id;
   UInt32 seq;
 
diff --git a/src/lib/server/ClientProxy1_6.h b/src/lib/server/ClientProxy1_6.h
index b619ffacf..2096cc399 100644
--- a/src/lib/server/ClientProxy1_6.h
+++ b/src/lib/server/ClientProxy1_6.h
@@ -26,7 +26,7 @@ class IEventQueue;
 class ClientProxy1_6 : public ClientProxy1_5
 {
 public:
-  ClientProxy1_6(const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
+  ClientProxy1_6(const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
   ~ClientProxy1_6();
 
   virtual void setClipboard(ClipboardID id, const IClipboard *clipboard);
diff --git a/src/lib/server/ClientProxy1_7.cpp b/src/lib/server/ClientProxy1_7.cpp
index 5f0f10b6c..62a187309 100644
--- a/src/lib/server/ClientProxy1_7.cpp
+++ b/src/lib/server/ClientProxy1_7.cpp
@@ -26,13 +26,13 @@
 // ClientProxy1_7
 //
 
-ClientProxy1_7::ClientProxy1_7(const String &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
+ClientProxy1_7::ClientProxy1_7(const std::string &name, deskflow::IStream *stream, Server *server, IEventQueue *events)
     : ClientProxy1_6(name, stream, server, events),
       m_events(events)
 {
 }
 
-void ClientProxy1_7::secureInputNotification(const String &app) const
+void ClientProxy1_7::secureInputNotification(const std::string &app) const
 {
   LOG((CLOG_DEBUG2 "send secure input notification to \"%s\" %s", getName().c_str(), app.c_str()));
   ProtocolUtil::writef(getStream(), kMsgDSecureInputNotification, &app);
diff --git a/src/lib/server/ClientProxy1_7.h b/src/lib/server/ClientProxy1_7.h
index a0a5ea6b8..36858ebf2 100644
--- a/src/lib/server/ClientProxy1_7.h
+++ b/src/lib/server/ClientProxy1_7.h
@@ -23,10 +23,10 @@
 class ClientProxy1_7 : public ClientProxy1_6
 {
 public:
-  ClientProxy1_7(const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
+  ClientProxy1_7(const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
   ~ClientProxy1_7() override = default;
 
-  void secureInputNotification(const String &app) const override;
+  void secureInputNotification(const std::string &app) const override;
 
 private:
   IEventQueue *m_events;
diff --git a/src/lib/server/ClientProxy1_8.cpp b/src/lib/server/ClientProxy1_8.cpp
index 8a563a89e..5433c02a3 100644
--- a/src/lib/server/ClientProxy1_8.cpp
+++ b/src/lib/server/ClientProxy1_8.cpp
@@ -21,7 +21,7 @@
 #include "ClientProxy1_8.h"
 
 ClientProxy1_8::ClientProxy1_8(
-    const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events
+    const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events
 )
     : ClientProxy1_7(name, adoptedStream, server, events)
 {
@@ -40,7 +40,7 @@ void ClientProxy1_8::synchronizeLanguages() const
   }
 }
 
-void ClientProxy1_8::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const String &language)
+void ClientProxy1_8::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const std::string &language)
 {
   LOG(
       (CLOG_DEBUG1 "send key down to \"%s\" id=%d, mask=0x%04x, button=0x%04x, language=%s", getName().c_str(), key,
diff --git a/src/lib/server/ClientProxy1_8.h b/src/lib/server/ClientProxy1_8.h
index 6d0807dd2..343ac8009 100644
--- a/src/lib/server/ClientProxy1_8.h
+++ b/src/lib/server/ClientProxy1_8.h
@@ -21,10 +21,10 @@
 class ClientProxy1_8 : public ClientProxy1_7
 {
 public:
-  ClientProxy1_8(const String &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
+  ClientProxy1_8(const std::string &name, deskflow::IStream *adoptedStream, Server *server, IEventQueue *events);
   ~ClientProxy1_8() override = default;
 
-  void keyDown(KeyID, KeyModifierMask, KeyButton, const String &) override;
+  void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &) override;
 
 private:
   void synchronizeLanguages() const;
diff --git a/src/lib/server/ClientProxyUnknown.cpp b/src/lib/server/ClientProxyUnknown.cpp
index de202660c..f4dc3f1b5 100644
--- a/src/lib/server/ClientProxyUnknown.cpp
+++ b/src/lib/server/ClientProxyUnknown.cpp
@@ -168,7 +168,7 @@ void ClientProxyUnknown::removeTimer()
   }
 }
 
-void ClientProxyUnknown::initProxy(const String &name, int major, int minor)
+void ClientProxyUnknown::initProxy(const std::string &name, int major, int minor)
 {
   if (major == 1) {
     switch (minor) {
@@ -220,7 +220,7 @@ void ClientProxyUnknown::handleData(const Event &, void *)
 {
   LOG((CLOG_DEBUG1 "parsing hello reply"));
 
-  String name("<unknown>");
+  std::string name("<unknown>");
 
   try {
     // limit the maximum length of the hello
diff --git a/src/lib/server/ClientProxyUnknown.h b/src/lib/server/ClientProxyUnknown.h
index d53c84246..f3e9bdc3b 100644
--- a/src/lib/server/ClientProxyUnknown.h
+++ b/src/lib/server/ClientProxyUnknown.h
@@ -20,9 +20,10 @@
 
 #include "base/Event.h"
 #include "base/EventTypes.h"
-#include "base/String.h"
 #include "deskflow/option_types.h"
 
+#include <string>
+
 class ClientProxy;
 class EventQueueTimer;
 namespace deskflow {
@@ -67,7 +68,7 @@ private:
   void addStreamHandlers();
   void addProxyHandlers();
   void removeHandlers();
-  void initProxy(const String &name, int major, int minor);
+  void initProxy(const std::string &name, int major, int minor);
   void removeTimer();
   void handleData(const Event &, void *);
   void handleWriteError(const Event &, void *);
diff --git a/src/lib/server/Config.cpp b/src/lib/server/Config.cpp
index 078e12180..53fccbd11 100644
--- a/src/lib/server/Config.cpp
+++ b/src/lib/server/Config.cpp
@@ -51,7 +51,7 @@ Config::~Config()
   // do nothing
 }
 
-bool Config::addScreen(const String &name)
+bool Config::addScreen(const std::string &name)
 {
   // alias name must not exist
   if (m_nameToCanonicalName.find(name) != m_nameToCanonicalName.end()) {
@@ -67,10 +67,10 @@ bool Config::addScreen(const String &name)
   return true;
 }
 
-bool Config::renameScreen(const String &oldName, const String &newName)
+bool Config::renameScreen(const std::string &oldName, const std::string &newName)
 {
   // get canonical name and find cell
-  String oldCanonical = getCanonicalName(oldName);
+  std::string oldCanonical = getCanonicalName(oldName);
   CellMap::iterator index = m_map.find(oldCanonical);
   if (index == m_map.end()) {
     return false;
@@ -109,10 +109,10 @@ bool Config::renameScreen(const String &oldName, const String &newName)
   return true;
 }
 
-void Config::removeScreen(const String &name)
+void Config::removeScreen(const std::string &name)
 {
   // get canonical name and find cell
-  String canonical = getCanonicalName(name);
+  std::string canonical = getCanonicalName(name);
   CellMap::iterator index = m_map.find(canonical);
   if (index == m_map.end()) {
     return;
@@ -143,7 +143,7 @@ void Config::removeAllScreens()
   m_nameToCanonicalName.clear();
 }
 
-bool Config::addAlias(const String &canonical, const String &alias)
+bool Config::addAlias(const std::string &canonical, const std::string &alias)
 {
   // alias name must not exist
   if (m_nameToCanonicalName.find(alias) != m_nameToCanonicalName.end()) {
@@ -161,7 +161,7 @@ bool Config::addAlias(const String &canonical, const String &alias)
   return true;
 }
 
-bool Config::removeAlias(const String &alias)
+bool Config::removeAlias(const std::string &alias)
 {
   // must not be a canonical name
   if (m_map.find(alias) != m_map.end()) {
@@ -180,7 +180,7 @@ bool Config::removeAlias(const String &alias)
   return true;
 }
 
-bool Config::removeAliases(const String &canonical)
+bool Config::removeAliases(const std::string &canonical)
 {
   // must be a canonical name
   if (m_map.find(canonical) == m_map.end()) {
@@ -211,8 +211,8 @@ void Config::removeAllAliases()
 }
 
 bool Config::connect(
-    const String &srcName, EDirection srcSide, float srcStart, float srcEnd, const String &dstName, float dstStart,
-    float dstEnd
+    const std::string &srcName, EDirection srcSide, float srcStart, float srcEnd, const std::string &dstName,
+    float dstStart, float dstEnd
 )
 {
   assert(srcSide >= kFirstDirection && srcSide <= kLastDirection);
@@ -229,7 +229,7 @@ bool Config::connect(
   return index->second.add(srcEdge, dstEdge);
 }
 
-bool Config::disconnect(const String &srcName, EDirection srcSide)
+bool Config::disconnect(const std::string &srcName, EDirection srcSide)
 {
   assert(srcSide >= kFirstDirection && srcSide <= kLastDirection);
 
@@ -245,7 +245,7 @@ bool Config::disconnect(const String &srcName, EDirection srcSide)
   return true;
 }
 
-bool Config::disconnect(const String &srcName, EDirection srcSide, float position)
+bool Config::disconnect(const std::string &srcName, EDirection srcSide, float position)
 {
   assert(srcSide >= kFirstDirection && srcSide <= kLastDirection);
 
@@ -266,7 +266,7 @@ void Config::setDeskflowAddress(const NetworkAddress &addr)
   m_deskflowAddress = addr;
 }
 
-bool Config::addOption(const String &name, OptionID option, OptionValue value)
+bool Config::addOption(const std::string &name, OptionID option, OptionValue value)
 {
   // find options
   ScreenOptions *options = NULL;
@@ -287,7 +287,7 @@ bool Config::addOption(const String &name, OptionID option, OptionValue value)
   return true;
 }
 
-bool Config::removeOption(const String &name, OptionID option)
+bool Config::removeOption(const std::string &name, OptionID option)
 {
   // find options
   ScreenOptions *options = NULL;
@@ -308,7 +308,7 @@ bool Config::removeOption(const String &name, OptionID option)
   return true;
 }
 
-bool Config::removeOptions(const String &name)
+bool Config::removeOptions(const std::string &name)
 {
   // find options
   ScreenOptions *options = NULL;
@@ -329,7 +329,7 @@ bool Config::removeOptions(const String &name)
   return true;
 }
 
-bool Config::isValidScreenName(const String &name) const
+bool Config::isValidScreenName(const std::string &name) const
 {
   // name is valid if matches validname
   //  name      ::= [_A-Za-z0-9] | [_A-Za-z0-9][-_A-Za-z0-9]*[_A-Za-z0-9]
@@ -344,7 +344,7 @@ bool Config::isValidScreenName(const String &name) const
   }
 
   // check each dot separated part
-  String::size_type b = 0;
+  std::string::size_type b = 0;
   for (;;) {
     // accept trailing .
     if (b == name.size()) {
@@ -352,8 +352,8 @@ bool Config::isValidScreenName(const String &name) const
     }
 
     // find end of part
-    String::size_type e = name.find('.', b);
-    if (e == String::npos) {
+    std::string::size_type e = name.find('.', b);
+    if (e == std::string::npos) {
       e = name.size();
     }
 
@@ -368,7 +368,7 @@ bool Config::isValidScreenName(const String &name) const
     }
 
     // check interior characters
-    for (String::size_type i = b; i < e; ++i) {
+    for (std::string::size_type i = b; i < e; ++i) {
       if (!isalnum(name[i]) && name[i] != '_' && name[i] != '-') {
         return false;
       }
@@ -405,34 +405,35 @@ Config::all_const_iterator Config::endAll() const
   return m_nameToCanonicalName.end();
 }
 
-bool Config::isScreen(const String &name) const
+bool Config::isScreen(const std::string &name) const
 {
   return (m_nameToCanonicalName.count(name) > 0);
 }
 
-bool Config::isCanonicalName(const String &name) const
+bool Config::isCanonicalName(const std::string &name) const
 {
   return (!name.empty() && CaselessCmp::equal(getCanonicalName(name), name));
 }
 
-String Config::getCanonicalName(const String &name) const
+std::string Config::getCanonicalName(const std::string &name) const
 {
   NameMap::const_iterator index = m_nameToCanonicalName.find(name);
   if (index == m_nameToCanonicalName.end()) {
-    return String();
+    return std::string();
   } else {
     return index->second;
   }
 }
 
-String Config::getNeighbor(const String &srcName, EDirection srcSide, float position, float *positionOut) const
+std::string
+Config::getNeighbor(const std::string &srcName, EDirection srcSide, float position, float *positionOut) const
 {
   assert(srcSide >= kFirstDirection && srcSide <= kLastDirection);
 
   // find source cell
   CellMap::const_iterator index = m_map.find(getCanonicalName(srcName));
   if (index == m_map.end()) {
-    return String();
+    return std::string();
   }
 
   // find edge
@@ -451,12 +452,12 @@ String Config::getNeighbor(const String &srcName, EDirection srcSide, float posi
   }
 }
 
-bool Config::hasNeighbor(const String &srcName, EDirection srcSide) const
+bool Config::hasNeighbor(const std::string &srcName, EDirection srcSide) const
 {
   return hasNeighbor(srcName, srcSide, 0.0f, 1.0f);
 }
 
-bool Config::hasNeighbor(const String &srcName, EDirection srcSide, float start, float end) const
+bool Config::hasNeighbor(const std::string &srcName, EDirection srcSide, float start, float end) const
 {
   assert(srcSide >= kFirstDirection && srcSide <= kLastDirection);
 
@@ -469,14 +470,14 @@ bool Config::hasNeighbor(const String &srcName, EDirection srcSide, float start,
   return index->second.overlaps(CellEdge(srcSide, Interval(start, end)));
 }
 
-Config::link_const_iterator Config::beginNeighbor(const String &srcName) const
+Config::link_const_iterator Config::beginNeighbor(const std::string &srcName) const
 {
   CellMap::const_iterator index = m_map.find(getCanonicalName(srcName));
   assert(index != m_map.end());
   return index->second.begin();
 }
 
-Config::link_const_iterator Config::endNeighbor(const String &srcName) const
+Config::link_const_iterator Config::endNeighbor(const std::string &srcName) const
 {
   CellMap::const_iterator index = m_map.find(getCanonicalName(srcName));
   assert(index != m_map.end());
@@ -488,7 +489,7 @@ const NetworkAddress &Config::getDeskflowAddress() const
   return m_deskflowAddress;
 }
 
-const Config::ScreenOptions *Config::getOptions(const String &name) const
+const Config::ScreenOptions *Config::getOptions(const std::string &name) const
 {
   // find options
   const ScreenOptions *options = NULL;
@@ -588,7 +589,7 @@ InputFilter *Config::getInputFilter()
   return &m_inputFilter;
 }
 
-String Config::formatInterval(const Interval &x)
+std::string Config::formatInterval(const Interval &x)
 {
   if (x.first == 0.0f && x.second == 1.0f) {
     return "";
@@ -596,7 +597,7 @@ String Config::formatInterval(const Interval &x)
   return deskflow::string::sprintf("(%d,%d)", (int)(x.first * 100.0f + 0.5f), (int)(x.second * 100.0f + 0.5f));
 }
 
-String Config::getClientAddress() const
+std::string Config::getClientAddress() const
 {
   return m_ClientAddress;
 }
@@ -614,7 +615,7 @@ void Config::readSection(ConfigReadContext &s)
   static const char s_links[] = "links";
   static const char s_aliases[] = "aliases";
 
-  String line;
+  std::string line;
   if (!s.readLine(line)) {
     // no more sections
     return;
@@ -626,13 +627,13 @@ void Config::readSection(ConfigReadContext &s)
   }
 
   // get section name
-  String::size_type i = line.find_first_not_of(" \t", sizeof(s_section) - 1);
-  if (i == String::npos) {
+  std::string::size_type i = line.find_first_not_of(" \t", sizeof(s_section) - 1);
+  if (i == std::string::npos) {
     throw XConfigRead(s, "section name is missing");
   }
-  String name = line.substr(i);
+  std::string name = line.substr(i);
   i = name.find_first_of(" \t");
-  if (i != String::npos) {
+  if (i != std::string::npos) {
     throw XConfigRead(s, "unexpected data after section name");
   }
 
@@ -652,7 +653,7 @@ void Config::readSection(ConfigReadContext &s)
 
 void Config::readSectionOptions(ConfigReadContext &s)
 {
-  String line;
+  std::string line;
   while (s.readLine(line)) {
     // check for end of section
     if (line == "end") {
@@ -663,8 +664,8 @@ void Config::readSectionOptions(ConfigReadContext &s)
     //   nameAndArgs  := <name>[(arg[,...])]
     //   values       := valueAndArgs[,valueAndArgs]...
     //   valueAndArgs := <value>[(arg[,...])]
-    String::size_type i = 0;
-    String name, value;
+    std::string::size_type i = 0;
+    std::string name, value;
     ConfigReadContext::ArgList nameArgs, valueArgs;
     s.parseNameWithArgs("name", line, "=", i, name, nameArgs);
     ++i;
@@ -676,7 +677,7 @@ void Config::readSectionOptions(ConfigReadContext &s)
         m_deskflowAddress = NetworkAddress(value, kDefaultPort);
         m_deskflowAddress.resolve();
       } catch (XSocketAddress &e) {
-        throw XConfigRead(s, String("invalid address argument ") + e.what());
+        throw XConfigRead(s, std::string("invalid address argument ") + e.what());
       }
     } else if (name == "heartbeat") {
       addOption("", kOptionHeartbeat, s.parseInt(value));
@@ -737,7 +738,7 @@ void Config::readSectionOptions(ConfigReadContext &s)
       if (i < line.length() && line[i] == ';') {
         // allow trailing ';'
         i = line.find_first_not_of(" \t", i + 1);
-        if (i == String::npos) {
+        if (i == std::string::npos) {
           i = line.length();
         } else {
           --i;
@@ -760,8 +761,8 @@ void Config::readSectionOptions(ConfigReadContext &s)
 
 void Config::readSectionScreens(ConfigReadContext &s)
 {
-  String line;
-  String screen;
+  std::string line;
+  std::string screen;
   while (s.readLine(line)) {
     // check for end of section
     if (line == "end") {
@@ -786,21 +787,21 @@ void Config::readSectionScreens(ConfigReadContext &s)
       throw XConfigRead(s, "argument before first screen");
     } else {
       // parse argument:  `<name>=<value>'
-      String::size_type i = line.find_first_of(" \t=");
+      std::string::size_type i = line.find_first_of(" \t=");
       if (i == 0) {
         throw XConfigRead(s, "missing argument name");
       }
-      if (i == String::npos) {
+      if (i == std::string::npos) {
         throw XConfigRead(s, "missing =");
       }
-      String name = line.substr(0, i);
+      std::string name = line.substr(0, i);
       i = line.find_first_not_of(" \t", i);
-      if (i == String::npos || line[i] != '=') {
+      if (i == std::string::npos || line[i] != '=') {
         throw XConfigRead(s, "missing =");
       }
       i = line.find_first_not_of(" \t", i + 1);
-      String value;
-      if (i != String::npos) {
+      std::string value;
+      if (i != std::string::npos) {
         value = line.substr(i);
       }
 
@@ -842,8 +843,8 @@ void Config::readSectionScreens(ConfigReadContext &s)
 
 void Config::readSectionLinks(ConfigReadContext &s)
 {
-  String line;
-  String screen;
+  std::string line;
+  std::string screen;
   while (s.readLine(line)) {
     // check for end of section
     if (line == "end") {
@@ -869,8 +870,8 @@ void Config::readSectionLinks(ConfigReadContext &s)
       // the stuff in brackets is optional.  interval values must be
       // in the range [0,100] and start < end.  if not given the
       // interval is taken to be (0,100).
-      String::size_type i = 0;
-      String side, dstScreen, srcArgString, dstArgString;
+      std::string::size_type i = 0;
+      std::string side, dstScreen, srcArgString, dstArgString;
       ConfigReadContext::ArgList srcArgs, dstArgs;
       s.parseNameWithArgs("link", line, "=", i, side, srcArgs);
       ++i;
@@ -907,8 +908,8 @@ void Config::readSectionLinks(ConfigReadContext &s)
 
 void Config::readSectionAliases(ConfigReadContext &s)
 {
-  String line;
-  String screen;
+  std::string line;
+  std::string screen;
   while (s.readLine(line)) {
     // check for end of section
     if (line == "end") {
@@ -945,7 +946,7 @@ void Config::readSectionAliases(ConfigReadContext &s)
 }
 
 InputFilter::Condition *
-Config::parseCondition(ConfigReadContext &s, const String &name, const std::vector<String> &args)
+Config::parseCondition(ConfigReadContext &s, const std::string &name, const std::vector<std::string> &args)
 {
   if (name == "keystroke") {
     if (args.size() != 1) {
@@ -972,7 +973,7 @@ Config::parseCondition(ConfigReadContext &s, const String &name, const std::vect
       throw XConfigRead(s, "syntax for condition: connect([screen])");
     }
 
-    String screen = args[0];
+    std::string screen = args[0];
     if (isScreen(screen)) {
       screen = getCanonicalName(screen);
     } else if (!screen.empty()) {
@@ -986,7 +987,8 @@ Config::parseCondition(ConfigReadContext &s, const String &name, const std::vect
 }
 
 void Config::parseAction(
-    ConfigReadContext &s, const String &name, const std::vector<String> &args, InputFilter::Rule &rule, bool activate
+    ConfigReadContext &s, const std::string &name, const std::vector<std::string> &args, InputFilter::Rule &rule,
+    bool activate
 )
 {
   InputFilter::Action *action;
@@ -1000,7 +1002,7 @@ void Config::parseAction(
     if (args.size() == 1) {
       keyInfo = s.parseKeystroke(args[0]);
     } else {
-      std::set<String> screens;
+      std::set<std::string> screens;
       parseScreens(s, args[1], screens);
       keyInfo = s.parseKeystroke(args[0], screens);
     }
@@ -1056,7 +1058,7 @@ void Config::parseAction(
       throw XConfigRead(s, "syntax for action: switchToScreen(name)");
     }
 
-    String screen = args[0];
+    std::string screen = args[0];
     if (isScreen(screen)) {
       screen = getCanonicalName(screen);
     } else if (!screen.empty()) {
@@ -1151,7 +1153,7 @@ void Config::parseAction(
       }
     }
 
-    std::set<String> screens;
+    std::set<std::string> screens;
     if (args.size() >= 2) {
       parseScreens(s, args[1], screens);
     }
@@ -1166,20 +1168,20 @@ void Config::parseAction(
   rule.adoptAction(action, activate);
 }
 
-void Config::parseScreens(ConfigReadContext &c, const String &s, std::set<String> &screens) const
+void Config::parseScreens(ConfigReadContext &c, const std::string &s, std::set<std::string> &screens) const
 {
   screens.clear();
 
-  String::size_type i = 0;
+  std::string::size_type i = 0;
   while (i < s.size()) {
     // find end of next screen name
-    String::size_type j = s.find(':', i);
-    if (j == String::npos) {
+    std::string::size_type j = s.find(':', i);
+    if (j == std::string::npos) {
       j = s.size();
     }
 
     // extract name
-    String rawName;
+    std::string rawName;
     i = s.find_first_not_of(" \t", i);
     if (i < j) {
       rawName = s.substr(i, s.find_last_not_of(" \t", j - 1) - i + 1);
@@ -1189,7 +1191,7 @@ void Config::parseScreens(ConfigReadContext &c, const String &s, std::set<String
     if (rawName == "*") {
       screens.insert("*");
     } else if (!rawName.empty()) {
-      String name = getCanonicalName(rawName);
+      std::string name = getCanonicalName(rawName);
       if (name.empty()) {
         throw XConfigRead(c, "unknown screen name \"%{1}\"", rawName);
       }
@@ -1278,7 +1280,7 @@ const char *Config::getOptionName(OptionID id)
   return NULL;
 }
 
-String Config::getOptionValue(OptionID id, OptionValue value)
+std::string Config::getOptionValue(OptionID id, OptionValue value)
 {
   if (id == kOptionHalfDuplexCapsLock || id == kOptionHalfDuplexNumLock || id == kOptionHalfDuplexScrollLock ||
       id == kOptionScreenSwitchNeedsShift || id == kOptionScreenSwitchNeedsControl ||
@@ -1351,14 +1353,14 @@ String Config::getOptionValue(OptionID id, OptionValue value)
 // Config::Name
 //
 
-Config::Name::Name(Config *config, const String &name) : m_config(config), m_name(config->getCanonicalName(name))
+Config::Name::Name(Config *config, const std::string &name) : m_config(config), m_name(config->getCanonicalName(name))
 {
   // do nothing
 }
 
-bool Config::Name::operator==(const String &name) const
+bool Config::Name::operator==(const std::string &name) const
 {
-  String canonical = m_config->getCanonicalName(name);
+  std::string canonical = m_config->getCanonicalName(name);
   return CaselessCmp::equal(canonical, m_name);
 }
 
@@ -1380,7 +1382,7 @@ Config::CellEdge::CellEdge(EDirection side, const Interval &interval)
   init("", side, interval);
 }
 
-Config::CellEdge::CellEdge(const String &name, EDirection side, const Interval &interval)
+Config::CellEdge::CellEdge(const std::string &name, EDirection side, const Interval &interval)
 {
   assert(interval.first >= 0.0f);
   assert(interval.second <= 1.0f);
@@ -1394,7 +1396,7 @@ Config::CellEdge::~CellEdge()
   // do nothing
 }
 
-void Config::CellEdge::init(const String &name, EDirection side, const Interval &interval)
+void Config::CellEdge::init(const std::string &name, EDirection side, const Interval &interval)
 {
   assert(side != kNoDirection);
 
@@ -1408,12 +1410,12 @@ Config::Interval Config::CellEdge::getInterval() const
   return m_interval;
 }
 
-void Config::CellEdge::setName(const String &newName)
+void Config::CellEdge::setName(const std::string &newName)
 {
   m_name = newName;
 }
 
-String Config::CellEdge::getName() const
+std::string Config::CellEdge::getName() const
 {
   return m_name;
 }
@@ -1518,7 +1520,7 @@ void Config::Cell::remove(const Name &name)
   }
 }
 
-void Config::Cell::rename(const Name &oldName, const String &newName)
+void Config::Cell::rename(const Name &oldName, const std::string &newName)
 {
   for (EdgeLinks::iterator j = m_neighbors.begin(); j != m_neighbors.end(); ++j) {
     if (oldName == j->second.getName()) {
@@ -1629,7 +1631,7 @@ std::ostream &operator<<(std::ostream &s, const Config &config)
     if (options != NULL && options->size() > 0) {
       for (Config::ScreenOptions::const_iterator option = options->begin(); option != options->end(); ++option) {
         const char *name = Config::getOptionName(option->first);
-        String value = Config::getOptionValue(option->first, option->second);
+        std::string value = Config::getOptionValue(option->first, option->second);
         if (name != NULL && !value.empty()) {
           s << "\t\t" << name << " = " << value << std::endl;
         }
@@ -1639,7 +1641,7 @@ std::ostream &operator<<(std::ostream &s, const Config &config)
   s << "end" << std::endl;
 
   // links section
-  String neighbor;
+  std::string neighbor;
   s << "section: links" << std::endl;
   for (Config::const_iterator screen = config.begin(); screen != config.end(); ++screen) {
     s << "\t" << screen->c_str() << ":" << std::endl;
@@ -1655,7 +1657,7 @@ std::ostream &operator<<(std::ostream &s, const Config &config)
   // aliases section (if there are any)
   if (config.m_map.size() != config.m_nameToCanonicalName.size()) {
     // map canonical to alias
-    using CMNameMap = std::multimap<String, String, CaselessCmp>;
+    using CMNameMap = std::multimap<std::string, std::string, CaselessCmp>;
     CMNameMap aliases;
     for (Config::NameMap::const_iterator index = config.m_nameToCanonicalName.begin();
          index != config.m_nameToCanonicalName.end(); ++index) {
@@ -1665,7 +1667,7 @@ std::ostream &operator<<(std::ostream &s, const Config &config)
     }
 
     // dump it
-    String screen;
+    std::string screen;
     s << "section: aliases" << std::endl;
     for (CMNameMap::const_iterator index = aliases.begin(); index != aliases.end(); ++index) {
       if (index->first != screen) {
@@ -1683,7 +1685,7 @@ std::ostream &operator<<(std::ostream &s, const Config &config)
   if (options != NULL && options->size() > 0) {
     for (Config::ScreenOptions::const_iterator option = options->begin(); option != options->end(); ++option) {
       const char *name = Config::getOptionName(option->first);
-      String value = Config::getOptionValue(option->first, option->second);
+      std::string value = Config::getOptionValue(option->first, option->second);
       if (name != NULL && !value.empty()) {
         s << "\t" << name << " = " << value << std::endl;
       }
@@ -1712,23 +1714,23 @@ ConfigReadContext::~ConfigReadContext()
   // do nothing
 }
 
-bool ConfigReadContext::readLine(String &line)
+bool ConfigReadContext::readLine(std::string &line)
 {
   ++m_line;
   while (std::getline(m_stream, line)) {
     // strip leading whitespace
-    String::size_type i = line.find_first_not_of(" \t");
-    if (i != String::npos) {
+    std::string::size_type i = line.find_first_not_of(" \t");
+    if (i != std::string::npos) {
       line.erase(0, i);
     }
 
     // strip comments and then trailing whitespace
     i = line.find('#');
-    if (i != String::npos) {
+    if (i != std::string::npos) {
       line.erase(i);
     }
     i = line.find_last_not_of(" \r\t");
-    if (i != String::npos) {
+    if (i != std::string::npos) {
       line.erase(i + 1);
     }
 
@@ -1760,7 +1762,7 @@ bool ConfigReadContext::operator!() const
   return !m_stream;
 }
 
-OptionValue ConfigReadContext::parseBoolean(const String &arg) const
+OptionValue ConfigReadContext::parseBoolean(const std::string &arg) const
 {
   if (CaselessCmp::equal(arg, "true")) {
     return static_cast<OptionValue>(true);
@@ -1771,7 +1773,7 @@ OptionValue ConfigReadContext::parseBoolean(const String &arg) const
   throw XConfigRead(*this, "invalid boolean argument \"%{1}\"", arg);
 }
 
-OptionValue ConfigReadContext::parseInt(const String &arg) const
+OptionValue ConfigReadContext::parseInt(const std::string &arg) const
 {
   const char *s = arg.c_str();
   char *end;
@@ -1788,7 +1790,7 @@ OptionValue ConfigReadContext::parseInt(const String &arg) const
   return value;
 }
 
-OptionValue ConfigReadContext::parseModifierKey(const String &arg) const
+OptionValue ConfigReadContext::parseModifierKey(const std::string &arg) const
 {
   if (CaselessCmp::equal(arg, "shift")) {
     return static_cast<OptionValue>(kKeyModifierIDShift);
@@ -1814,7 +1816,7 @@ OptionValue ConfigReadContext::parseModifierKey(const String &arg) const
   throw XConfigRead(*this, "invalid argument \"%{1}\"", arg);
 }
 
-OptionValue ConfigReadContext::parseCorner(const String &arg) const
+OptionValue ConfigReadContext::parseCorner(const std::string &arg) const
 {
   if (CaselessCmp::equal(arg, "left")) {
     return kTopLeftMask | kBottomLeftMask;
@@ -1840,7 +1842,7 @@ OptionValue ConfigReadContext::parseCorner(const String &arg) const
   throw XConfigRead(*this, "invalid argument \"%{1}\"", arg);
 }
 
-OptionValue ConfigReadContext::parseProtocol(const String &args) const
+OptionValue ConfigReadContext::parseProtocol(const std::string &args) const
 {
   if (CaselessCmp::equal(args, kSynergyProtocolOption)) {
     return static_cast<OptionValue>(ENetworkProtocol::kSynergy);
@@ -1850,21 +1852,21 @@ OptionValue ConfigReadContext::parseProtocol(const String &args) const
   throw XConfigRead(*this, "invalid protocol argument \"%{1}\"", args);
 }
 
-OptionValue ConfigReadContext::parseCorners(const String &args) const
+OptionValue ConfigReadContext::parseCorners(const std::string &args) const
 {
   // find first token
-  String::size_type i = args.find_first_not_of(" \t", 0);
-  if (i == String::npos) {
+  std::string::size_type i = args.find_first_not_of(" \t", 0);
+  if (i == std::string::npos) {
     throw XConfigRead(*this, "missing corner argument");
   }
-  String::size_type j = args.find_first_of(" \t", i);
+  std::string::size_type j = args.find_first_of(" \t", i);
 
   // parse first corner token
   OptionValue corners = parseCorner(args.substr(i, j - i));
 
   // get +/-
   i = args.find_first_not_of(" \t", j);
-  while (i != String::npos) {
+  while (i != std::string::npos) {
     // parse +/-
     bool add;
     if (args[i] == '-') {
@@ -1872,13 +1874,13 @@ OptionValue ConfigReadContext::parseCorners(const String &args) const
     } else if (args[i] == '+') {
       add = true;
     } else {
-      throw XConfigRead(*this, "invalid corner operator \"%{1}\"", String(args.c_str() + i, 1));
+      throw XConfigRead(*this, "invalid corner operator \"%{1}\"", std::string(args.c_str() + i, 1));
     }
 
     // get next corner token
     i = args.find_first_not_of(" \t", i + 1);
     j = args.find_first_of(" \t", i);
-    if (i == String::npos) {
+    if (i == std::string::npos) {
       throw XConfigRead(*this, "missing corner argument");
     }
 
@@ -1923,18 +1925,19 @@ Config::Interval ConfigReadContext::parseInterval(const ArgList &args) const
 }
 
 void ConfigReadContext::parseNameWithArgs(
-    const String &type, const String &line, const String &delim, String::size_type &index, String &name, ArgList &args
+    const std::string &type, const std::string &line, const std::string &delim, std::string::size_type &index,
+    std::string &name, ArgList &args
 ) const
 {
   // skip leading whitespace
-  String::size_type i = line.find_first_not_of(" \t", index);
-  if (i == String::npos) {
-    throw XConfigRead(*this, String("missing ") + type);
+  std::string::size_type i = line.find_first_not_of(" \t", index);
+  if (i == std::string::npos) {
+    throw XConfigRead(*this, std::string("missing ") + type);
   }
 
   // find end of name
-  String::size_type j = line.find_first_of(" \t(" + delim, i);
-  if (j == String::npos) {
+  std::string::size_type j = line.find_first_of(" \t(" + delim, i);
+  if (j == std::string::npos) {
     j = line.length();
   }
 
@@ -1943,15 +1946,15 @@ void ConfigReadContext::parseNameWithArgs(
   args.clear();
 
   // is it okay to not find a delimiter?
-  bool needDelim = (!delim.empty() && delim.find('\n') == String::npos);
+  bool needDelim = (!delim.empty() && delim.find('\n') == std::string::npos);
 
   // skip whitespace
   i = line.find_first_not_of(" \t", j);
-  if (i == String::npos && needDelim) {
+  if (i == std::string::npos && needDelim) {
     // expected delimiter but didn't find it
-    throw XConfigRead(*this, String("missing ") + delim[0]);
+    throw XConfigRead(*this, std::string("missing ") + delim[0]);
   }
-  if (i == String::npos) {
+  if (i == std::string::npos) {
     // no arguments
     index = line.length();
     return;
@@ -1967,18 +1970,18 @@ void ConfigReadContext::parseNameWithArgs(
 
   // parse arguments
   j = line.find_first_of(",)", i);
-  while (j != String::npos) {
+  while (j != std::string::npos) {
     // extract arg
-    String arg(line.substr(i, j - i));
+    std::string arg(line.substr(i, j - i));
     i = j;
 
     // trim whitespace
     j = arg.find_first_not_of(" \t");
-    if (j != String::npos) {
+    if (j != std::string::npos) {
       arg.erase(0, j);
     }
     j = arg.find_last_not_of(" \t");
-    if (j != String::npos) {
+    if (j != std::string::npos) {
       arg.erase(j + 1);
     }
 
@@ -1998,7 +2001,7 @@ void ConfigReadContext::parseNameWithArgs(
   }
 
   // verify ')'
-  if (j == String::npos) {
+  if (j == std::string::npos) {
     // expected )
     throw XConfigRead(*this, "missing )");
   }
@@ -2008,17 +2011,17 @@ void ConfigReadContext::parseNameWithArgs(
 
   // skip whitespace
   j = line.find_first_not_of(" \t", i);
-  if (j == String::npos && needDelim) {
+  if (j == std::string::npos && needDelim) {
     // expected delimiter but didn't find it
-    throw XConfigRead(*this, String("missing ") + delim[0]);
+    throw XConfigRead(*this, std::string("missing ") + delim[0]);
   }
 
   // verify delimiter
-  if (needDelim && delim.find(line[j]) == String::npos) {
-    throw XConfigRead(*this, String("expected ") + delim[0]);
+  if (needDelim && delim.find(line[j]) == std::string::npos) {
+    throw XConfigRead(*this, std::string("expected ") + delim[0]);
   }
 
-  if (j == String::npos) {
+  if (j == std::string::npos) {
     j = line.length();
   }
 
@@ -2026,15 +2029,15 @@ void ConfigReadContext::parseNameWithArgs(
   return;
 }
 
-IPlatformScreen::KeyInfo *ConfigReadContext::parseKeystroke(const String &keystroke) const
+IPlatformScreen::KeyInfo *ConfigReadContext::parseKeystroke(const std::string &keystroke) const
 {
-  return parseKeystroke(keystroke, std::set<String>());
+  return parseKeystroke(keystroke, std::set<std::string>());
 }
 
 IPlatformScreen::KeyInfo *
-ConfigReadContext::parseKeystroke(const String &keystroke, const std::set<String> &screens) const
+ConfigReadContext::parseKeystroke(const std::string &keystroke, const std::set<std::string> &screens) const
 {
-  String s = keystroke;
+  std::string s = keystroke;
 
   KeyModifierMask mask;
   if (!deskflow::KeyMap::parseModifiers(s, mask)) {
@@ -2053,9 +2056,9 @@ ConfigReadContext::parseKeystroke(const String &keystroke, const std::set<String
   return IPlatformScreen::KeyInfo::alloc(key, mask, 0, 0, screens);
 }
 
-IPlatformScreen::ButtonInfo *ConfigReadContext::parseMouse(const String &mouse) const
+IPlatformScreen::ButtonInfo *ConfigReadContext::parseMouse(const std::string &mouse) const
 {
-  String s = mouse;
+  std::string s = mouse;
 
   KeyModifierMask mask;
   if (!deskflow::KeyMap::parseModifiers(s, mask)) {
@@ -2074,9 +2077,9 @@ IPlatformScreen::ButtonInfo *ConfigReadContext::parseMouse(const String &mouse)
   return IPlatformScreen::ButtonInfo::alloc(button, mask);
 }
 
-KeyModifierMask ConfigReadContext::parseModifier(const String &modifiers) const
+KeyModifierMask ConfigReadContext::parseModifier(const std::string &modifiers) const
 {
-  String s = modifiers;
+  std::string s = modifiers;
 
   KeyModifierMask mask;
   if (!deskflow::KeyMap::parseModifiers(s, mask)) {
@@ -2090,9 +2093,9 @@ KeyModifierMask ConfigReadContext::parseModifier(const String &modifiers) const
   return mask;
 }
 
-String ConfigReadContext::concatArgs(const ArgList &args)
+std::string ConfigReadContext::concatArgs(const ArgList &args)
 {
-  String s("(");
+  std::string s("(");
   for (size_t i = 0; i < args.size(); ++i) {
     if (i != 0) {
       s += ",";
@@ -2107,13 +2110,13 @@ String ConfigReadContext::concatArgs(const ArgList &args)
 // Config I/O exceptions
 //
 
-XConfigRead::XConfigRead(const ConfigReadContext &context, const String &error)
+XConfigRead::XConfigRead(const ConfigReadContext &context, const std::string &error)
     : m_error(deskflow::string::sprintf("line %d: %s", context.getLineNumber(), error.c_str()))
 {
   // do nothing
 }
 
-XConfigRead::XConfigRead(const ConfigReadContext &context, const char *errorFmt, const String &arg)
+XConfigRead::XConfigRead(const ConfigReadContext &context, const char *errorFmt, const std::string &arg)
     : m_error(
           deskflow::string::sprintf("line %d: ", context.getLineNumber()) +
           deskflow::string::format(errorFmt, arg.c_str())
@@ -2127,7 +2130,7 @@ XConfigRead::~XConfigRead() _NOEXCEPT
   // do nothing
 }
 
-String XConfigRead::getWhat() const throw()
+std::string XConfigRead::getWhat() const throw()
 {
   return format("XConfigRead", "read error: %{1}", m_error.c_str());
 }
diff --git a/src/lib/server/Config.h b/src/lib/server/Config.h
index 8c6b6a140..8452cef16 100644
--- a/src/lib/server/Config.h
+++ b/src/lib/server/Config.h
@@ -40,11 +40,11 @@ class IEventQueue;
 namespace std {
 template <> struct iterator_traits<deskflow::server::Config>
 {
-  using value_type = String;
+  using value_type = std::string;
   using difference_type = ptrdiff_t;
   using iterator_category = bidirectional_iterator_tag;
-  using pointer = String *;
-  using reference = String &;
+  using pointer = std::string *;
+  using reference = std::string &;
 };
 }; // namespace std
 
@@ -71,12 +71,12 @@ public:
   public:
     CellEdge(EDirection side, float position);
     CellEdge(EDirection side, const Interval &);
-    CellEdge(const String &name, EDirection side, const Interval &);
+    CellEdge(const std::string &name, EDirection side, const Interval &);
     ~CellEdge();
 
     Interval getInterval() const;
-    void setName(const String &newName);
-    String getName() const;
+    void setName(const std::string &newName);
+    std::string getName() const;
     EDirection getSide() const;
     bool overlaps(const CellEdge &) const;
     bool isInside(float x) const;
@@ -95,10 +95,10 @@ public:
     bool operator!=(const CellEdge &) const;
 
   private:
-    void init(const String &name, EDirection side, const Interval &);
+    void init(const std::string &name, EDirection side, const Interval &);
 
   private:
-    String m_name;
+    std::string m_name;
     EDirection m_side;
     Interval m_interval;
   };
@@ -107,13 +107,13 @@ private:
   class Name
   {
   public:
-    Name(Config *, const String &name);
+    Name(Config *, const std::string &name);
 
-    bool operator==(const String &name) const;
+    bool operator==(const std::string &name) const;
 
   private:
     Config *m_config;
-    String m_name;
+    std::string m_name;
   };
 
   class Cell
@@ -128,7 +128,7 @@ private:
     void remove(EDirection side);
     void remove(EDirection side, float position);
     void remove(const Name &destinationName);
-    void rename(const Name &oldName, const String &newName);
+    void rename(const Name &oldName, const std::string &newName);
 
     bool hasEdge(const CellEdge &) const;
     bool overlaps(const CellEdge &) const;
@@ -147,8 +147,8 @@ private:
   public:
     ScreenOptions m_options;
   };
-  using CellMap = std::map<String, Cell, deskflow::string::CaselessCmp>;
-  using NameMap = std::map<String, String, deskflow::string::CaselessCmp>;
+  using CellMap = std::map<std::string, Cell, deskflow::string::CaselessCmp>;
+  using NameMap = std::map<std::string, std::string, deskflow::string::CaselessCmp>;
 
 public:
   using link_const_iterator = Cell::const_iterator;
@@ -171,11 +171,11 @@ public:
       m_i = i.m_i;
       return *this;
     }
-    String operator*()
+    std::string operator*()
     {
       return m_i->first;
     }
-    const String *operator->()
+    const std::string *operator->()
     {
       return &(m_i->first);
     }
@@ -227,14 +227,14 @@ public:
   Adds a screen, returning true iff successful.  If a screen or
   alias with the given name exists then it fails.
   */
-  bool addScreen(const String &name);
+  bool addScreen(const std::string &name);
 
   //! Rename screen
   /*!
   Renames a screen.  All references to the name are updated.
   Returns true iff successful.
   */
-  bool renameScreen(const String &oldName, const String &newName);
+  bool renameScreen(const std::string &oldName, const std::string &newName);
 
   //! Remove screen
   /*!
@@ -242,7 +242,7 @@ public:
   disconnects any connections to the screen.  \c name may be an
   alias.
   */
-  void removeScreen(const String &name);
+  void removeScreen(const std::string &name);
 
   //! Remove all screens
   /*!
@@ -257,21 +257,21 @@ public:
   Returns false if the alias name already exists or the canonical
   name is unknown, otherwise returns true.
   */
-  bool addAlias(const String &canonical, const String &alias);
+  bool addAlias(const std::string &canonical, const std::string &alias);
 
   //! Remove alias
   /*!
   Removes an alias for a screen name.  It returns false if the
   alias is unknown or a canonical name, otherwise returns true.
   */
-  bool removeAlias(const String &alias);
+  bool removeAlias(const std::string &alias);
 
   //! Remove aliases
   /*!
   Removes all aliases for a canonical screen name.  It returns false
   if the canonical name is unknown, otherwise returns true.
   */
-  bool removeAliases(const String &canonical);
+  bool removeAliases(const std::string &canonical);
 
   //! Remove all aliases
   /*!
@@ -296,8 +296,8 @@ public:
   be inside the range [0,1].
   */
   bool connect(
-      const String &srcName, EDirection srcSide, float srcStart, float srcEnd, const String &dstName, float dstStart,
-      float dstEnd
+      const std::string &srcName, EDirection srcSide, float srcStart, float srcEnd, const std::string &dstName,
+      float dstStart, float dstEnd
   );
 
   //! Disconnect screens
@@ -305,7 +305,7 @@ public:
   Removes all connections created by connect() on side \c srcSide.
   Returns false if \c srcName is unknown.
   */
-  bool disconnect(const String &srcName, EDirection srcSide);
+  bool disconnect(const std::string &srcName, EDirection srcSide);
 
   //! Disconnect screens
   /*!
@@ -313,7 +313,7 @@ public:
   covering position \c position.  Returns false if \c srcName is
   unknown.
   */
-  bool disconnect(const String &srcName, EDirection srcSide, float position);
+  bool disconnect(const std::string &srcName, EDirection srcSide, float position);
 
   //! Set server address
   /*!
@@ -328,7 +328,7 @@ public:
   existing option's value if there is one.  Returns true iff \c name
   is a known screen.
   */
-  bool addOption(const String &name, OptionID option, OptionValue value);
+  bool addOption(const std::string &name, OptionID option, OptionValue value);
 
   //! Remove a screen option
   /*!
@@ -336,14 +336,14 @@ public:
   nothing if the option doesn't exist on the screen.  Returns true
   iff \c name is a known screen.
   */
-  bool removeOption(const String &name, OptionID option);
+  bool removeOption(const std::string &name, OptionID option);
 
   //! Remove a screen options
   /*!
   Removes all options and values from the named screen.  Returns true
   iff \c name is a known screen.
   */
-  bool removeOptions(const String &name);
+  bool removeOptions(const std::string &name);
 
   //! Get the hot key input filter
   /*!
@@ -360,7 +360,7 @@ public:
   /*!
   Returns true iff \c name is a valid screen name.
   */
-  bool isValidScreenName(const String &name) const;
+  bool isValidScreenName(const std::string &name) const;
 
   //! Get beginning (canonical) screen name iterator
   const_iterator begin() const;
@@ -376,20 +376,20 @@ public:
   /*!
   Returns true iff \c name names a screen.
   */
-  virtual bool isScreen(const String &name) const;
+  virtual bool isScreen(const std::string &name) const;
 
   //! Test for canonical screen name
   /*!
   Returns true iff \c name is the canonical name of a screen.
   */
-  bool isCanonicalName(const String &name) const;
+  bool isCanonicalName(const std::string &name) const;
 
   //! Get canonical name
   /*!
   Returns the canonical name of a screen or the empty string if
   the name is unknown.  Returns the canonical name if one is given.
   */
-  String getCanonicalName(const String &name) const;
+  std::string getCanonicalName(const std::string &name) const;
 
   //! Get neighbor
   /*!
@@ -399,26 +399,26 @@ public:
   saves the position on the neighbor in \c positionOut if it's not
   \c NULL.
   */
-  String getNeighbor(const String &, EDirection, float position, float *positionOut) const;
+  std::string getNeighbor(const std::string &, EDirection, float position, float *positionOut) const;
 
   //! Check for neighbor
   /*!
   Returns \c true if the screen has a neighbor anywhere along the edge
   given by the direction.
   */
-  bool hasNeighbor(const String &, EDirection) const;
+  bool hasNeighbor(const std::string &, EDirection) const;
 
   //! Check for neighbor
   /*!
   Returns \c true if the screen has a neighbor in the given range along
   the edge given by the direction.
   */
-  bool hasNeighbor(const String &, EDirection, float start, float end) const;
+  bool hasNeighbor(const std::string &, EDirection, float start, float end) const;
 
   //! Get beginning neighbor iterator
-  link_const_iterator beginNeighbor(const String &) const;
+  link_const_iterator beginNeighbor(const std::string &) const;
   //! Get ending neighbor iterator
-  link_const_iterator endNeighbor(const String &) const;
+  link_const_iterator endNeighbor(const std::string &) const;
 
   //! Get the server address
   const NetworkAddress &getDeskflowAddress() const;
@@ -429,7 +429,7 @@ public:
   if the screen is unknown and an empty collection if there are no
   options.
   */
-  const ScreenOptions *getOptions(const String &name) const;
+  const ScreenOptions *getOptions(const std::string &name) const;
 
   //! Check for lock to screen action
   /*!
@@ -472,13 +472,13 @@ public:
   /*!
   Returns an interval as a parseable string.
   */
-  static String formatInterval(const Interval &);
+  static std::string formatInterval(const Interval &);
 
   //! Get client address as a string
   /*!
    * Return client address a string.
    */
-  String getClientAddress() const;
+  std::string getClientAddress() const;
 
   //! Return true if server started in client mode
   /*!
@@ -495,14 +495,16 @@ private:
   void readSectionLinks(ConfigReadContext &);
   void readSectionAliases(ConfigReadContext &);
 
-  InputFilter::Condition *parseCondition(ConfigReadContext &, const String &condition, const std::vector<String> &args);
+  InputFilter::Condition *
+  parseCondition(ConfigReadContext &, const std::string &condition, const std::vector<std::string> &args);
   void parseAction(
-      ConfigReadContext &, const String &action, const std::vector<String> &args, InputFilter::Rule &, bool activate
+      ConfigReadContext &, const std::string &action, const std::vector<std::string> &args, InputFilter::Rule &,
+      bool activate
   );
 
-  void parseScreens(ConfigReadContext &, const String &, std::set<String> &screens) const;
+  void parseScreens(ConfigReadContext &, const std::string &, std::set<std::string> &screens) const;
   static const char *getOptionName(OptionID);
-  static String getOptionValue(OptionID, OptionValue);
+  static std::string getOptionValue(OptionID, OptionValue);
 
 private:
   CellMap m_map;
@@ -512,7 +514,7 @@ private:
   InputFilter m_inputFilter;
   bool m_hasLockToScreenAction;
   IEventQueue *m_events;
-  String m_ClientAddress;
+  std::string m_ClientAddress;
 };
 
 //! Configuration read context
@@ -522,30 +524,31 @@ Maintains a context when reading a configuration from a stream.
 class ConfigReadContext
 {
 public:
-  using ArgList = std::vector<String>;
+  using ArgList = std::vector<std::string>;
 
   ConfigReadContext(std::istream &, SInt32 firstLine = 1);
   ~ConfigReadContext();
 
-  bool readLine(String &);
+  bool readLine(std::string &);
   UInt32 getLineNumber() const;
 
   bool operator!() const;
 
-  OptionValue parseBoolean(const String &) const;
-  OptionValue parseInt(const String &) const;
-  OptionValue parseModifierKey(const String &) const;
-  OptionValue parseCorner(const String &) const;
-  OptionValue parseCorners(const String &) const;
-  OptionValue parseProtocol(const String &) const;
+  OptionValue parseBoolean(const std::string &) const;
+  OptionValue parseInt(const std::string &) const;
+  OptionValue parseModifierKey(const std::string &) const;
+  OptionValue parseCorner(const std::string &) const;
+  OptionValue parseCorners(const std::string &) const;
+  OptionValue parseProtocol(const std::string &) const;
   Config::Interval parseInterval(const ArgList &args) const;
   void parseNameWithArgs(
-      const String &type, const String &line, const String &delim, String::size_type &index, String &name, ArgList &args
+      const std::string &type, const std::string &line, const std::string &delim, std::string::size_type &index,
+      std::string &name, ArgList &args
   ) const;
-  IPlatformScreen::KeyInfo *parseKeystroke(const String &keystroke) const;
-  IPlatformScreen::KeyInfo *parseKeystroke(const String &keystroke, const std::set<String> &screens) const;
-  IPlatformScreen::ButtonInfo *parseMouse(const String &mouse) const;
-  KeyModifierMask parseModifier(const String &modifiers) const;
+  IPlatformScreen::KeyInfo *parseKeystroke(const std::string &keystroke) const;
+  IPlatformScreen::KeyInfo *parseKeystroke(const std::string &keystroke, const std::set<std::string> &screens) const;
+  IPlatformScreen::ButtonInfo *parseMouse(const std::string &mouse) const;
+  KeyModifierMask parseModifier(const std::string &modifiers) const;
   std::istream &getStream() const
   {
     return m_stream;
@@ -555,7 +558,7 @@ private:
   // not implemented
   ConfigReadContext &operator=(const ConfigReadContext &);
 
-  static String concatArgs(const ArgList &args);
+  static std::string concatArgs(const ArgList &args);
 
 private:
   std::istream &m_stream;
@@ -569,16 +572,16 @@ Thrown when a configuration stream cannot be parsed.
 class XConfigRead : public XBase
 {
 public:
-  XConfigRead(const ConfigReadContext &context, const String &);
-  XConfigRead(const ConfigReadContext &context, const char *errorFmt, const String &arg);
+  XConfigRead(const ConfigReadContext &context, const std::string &);
+  XConfigRead(const ConfigReadContext &context, const char *errorFmt, const std::string &arg);
   virtual ~XConfigRead() _NOEXCEPT;
 
 protected:
   // XBase overrides
-  virtual String getWhat() const throw();
+  virtual std::string getWhat() const throw();
 
 private:
-  String m_error;
+  std::string m_error;
 };
 
 } // namespace deskflow::server
diff --git a/src/lib/server/InputFilter.cpp b/src/lib/server/InputFilter.cpp
index 0c94b9086..56ad542a8 100644
--- a/src/lib/server/InputFilter.cpp
+++ b/src/lib/server/InputFilter.cpp
@@ -88,7 +88,7 @@ InputFilter::Condition *InputFilter::KeystrokeCondition::clone() const
   return new KeystrokeCondition(m_events, m_key, m_mask);
 }
 
-String InputFilter::KeystrokeCondition::format() const
+std::string InputFilter::KeystrokeCondition::format() const
 {
   return deskflow::string::sprintf("keystroke(%s)", deskflow::KeyMap::formatKey(m_key, m_mask).c_str());
 }
@@ -163,9 +163,9 @@ InputFilter::Condition *InputFilter::MouseButtonCondition::clone() const
   return new MouseButtonCondition(m_events, m_button, m_mask);
 }
 
-String InputFilter::MouseButtonCondition::format() const
+std::string InputFilter::MouseButtonCondition::format() const
 {
-  String key = deskflow::KeyMap::formatKey(kKeyNone, m_mask);
+  std::string key = deskflow::KeyMap::formatKey(kKeyNone, m_mask);
   if (!key.empty()) {
     key += "+";
   }
@@ -199,7 +199,7 @@ InputFilter::EFilterStatus InputFilter::MouseButtonCondition::match(const Event
   return status;
 }
 
-InputFilter::ScreenConnectedCondition::ScreenConnectedCondition(IEventQueue *events, const String &screen)
+InputFilter::ScreenConnectedCondition::ScreenConnectedCondition(IEventQueue *events, const std::string &screen)
     : m_screen(screen),
       m_events(events)
 {
@@ -216,7 +216,7 @@ InputFilter::Condition *InputFilter::ScreenConnectedCondition::clone() const
   return new ScreenConnectedCondition(m_events, m_screen);
 }
 
-String InputFilter::ScreenConnectedCondition::format() const
+std::string InputFilter::ScreenConnectedCondition::format() const
 {
   return deskflow::string::sprintf("connect(%s)", m_screen.c_str());
 }
@@ -263,7 +263,7 @@ InputFilter::Action *InputFilter::LockCursorToScreenAction::clone() const
   return new LockCursorToScreenAction(*this);
 }
 
-String InputFilter::LockCursorToScreenAction::format() const
+std::string InputFilter::LockCursorToScreenAction::format() const
 {
   static const char *s_mode[] = {"off", "on", "toggle"};
 
@@ -298,7 +298,7 @@ InputFilter::Action *InputFilter::RestartServer::clone() const
   return new RestartServer(*this);
 }
 
-String InputFilter::RestartServer::format() const
+std::string InputFilter::RestartServer::format() const
 {
   static const char *s_mode[] = {"restart"};
 
@@ -311,14 +311,14 @@ void InputFilter::RestartServer::perform(const Event &event)
   exit(0);
 }
 
-InputFilter::SwitchToScreenAction::SwitchToScreenAction(IEventQueue *events, const String &screen)
+InputFilter::SwitchToScreenAction::SwitchToScreenAction(IEventQueue *events, const std::string &screen)
     : m_screen(screen),
       m_events(events)
 {
   // do nothing
 }
 
-String InputFilter::SwitchToScreenAction::getScreen() const
+std::string InputFilter::SwitchToScreenAction::getScreen() const
 {
   return m_screen;
 }
@@ -328,7 +328,7 @@ InputFilter::Action *InputFilter::SwitchToScreenAction::clone() const
   return new SwitchToScreenAction(*this);
 }
 
-String InputFilter::SwitchToScreenAction::format() const
+std::string InputFilter::SwitchToScreenAction::format() const
 {
   return deskflow::string::sprintf("switchToScreen(%s)", m_screen.c_str());
 }
@@ -337,7 +337,7 @@ void InputFilter::SwitchToScreenAction::perform(const Event &event)
 {
   // pick screen name.  if m_screen is empty then use the screen from
   // event if it has one.
-  String screen = m_screen;
+  std::string screen = m_screen;
   if (screen.empty() && event.getType() == m_events->forServer().connected()) {
     Server::ScreenConnectedInfo *info = static_cast<Server::ScreenConnectedInfo *>(event.getData());
     screen = info->m_screen;
@@ -366,7 +366,7 @@ InputFilter::Action *InputFilter::SwitchInDirectionAction::clone() const
   return new SwitchInDirectionAction(*this);
 }
 
-String InputFilter::SwitchInDirectionAction::format() const
+std::string InputFilter::SwitchInDirectionAction::format() const
 {
   static const char *s_names[] = {"", "left", "right", "up", "down"};
 
@@ -389,7 +389,7 @@ InputFilter::KeyboardBroadcastAction::KeyboardBroadcastAction(IEventQueue *event
 }
 
 InputFilter::KeyboardBroadcastAction::KeyboardBroadcastAction(
-    IEventQueue *events, Mode mode, const std::set<String> &screens
+    IEventQueue *events, Mode mode, const std::set<std::string> &screens
 )
     : m_mode(mode),
       m_screens(IKeyState::KeyInfo::join(screens)),
@@ -403,9 +403,9 @@ InputFilter::KeyboardBroadcastAction::Mode InputFilter::KeyboardBroadcastAction:
   return m_mode;
 }
 
-std::set<String> InputFilter::KeyboardBroadcastAction::getScreens() const
+std::set<std::string> InputFilter::KeyboardBroadcastAction::getScreens() const
 {
-  std::set<String> screens;
+  std::set<std::string> screens;
   IKeyState::KeyInfo::split(m_screens.c_str(), screens);
   return screens;
 }
@@ -415,7 +415,7 @@ InputFilter::Action *InputFilter::KeyboardBroadcastAction::clone() const
   return new KeyboardBroadcastAction(*this);
 }
 
-String InputFilter::KeyboardBroadcastAction::format() const
+std::string InputFilter::KeyboardBroadcastAction::format() const
 {
   static const char *s_mode[] = {"off", "on", "toggle"};
   static const char *s_name = "keyboardBroadcast";
@@ -478,7 +478,7 @@ InputFilter::Action *InputFilter::KeystrokeAction::clone() const
   return new KeystrokeAction(m_events, info, m_press);
 }
 
-String InputFilter::KeystrokeAction::format() const
+std::string InputFilter::KeystrokeAction::format() const
 {
   const char *type = formatName();
 
@@ -545,11 +545,11 @@ InputFilter::Action *InputFilter::MouseButtonAction::clone() const
   return new MouseButtonAction(m_events, info, m_press);
 }
 
-String InputFilter::MouseButtonAction::format() const
+std::string InputFilter::MouseButtonAction::format() const
 {
   const char *type = formatName();
 
-  String key = deskflow::KeyMap::formatKey(kKeyNone, m_buttonInfo->m_mask);
+  std::string key = deskflow::KeyMap::formatKey(kKeyNone, m_buttonInfo->m_mask);
   return deskflow::string::sprintf("%s(%s%s%d)", type, key.c_str(), key.empty() ? "" : "+", m_buttonInfo->m_button);
 }
 
@@ -726,9 +726,9 @@ bool InputFilter::Rule::handleEvent(const Event &event)
   return true;
 }
 
-String InputFilter::Rule::format() const
+std::string InputFilter::Rule::format() const
 {
-  String s;
+  std::string s;
   if (m_condition != NULL) {
     // condition
     s += m_condition->format();
@@ -898,9 +898,9 @@ void InputFilter::setPrimaryClient(PrimaryClient *client)
   }
 }
 
-String InputFilter::format(const String &linePrefix) const
+std::string InputFilter::format(const std::string &linePrefix) const
 {
-  String s;
+  std::string s;
   for (RuleList::const_iterator i = m_ruleList.begin(); i != m_ruleList.end(); ++i) {
     s += linePrefix;
     s += i->format();
@@ -923,7 +923,7 @@ bool InputFilter::operator==(const InputFilter &x) const
 
   // compare rule lists.  the easiest way to do that is to format each
   // rule into a string, sort the strings, then compare the results.
-  std::vector<String> aList, bList;
+  std::vector<std::string> aList, bList;
   for (RuleList::const_iterator i = m_ruleList.begin(); i != m_ruleList.end(); ++i) {
     aList.push_back(i->format());
   }
diff --git a/src/lib/server/InputFilter.h b/src/lib/server/InputFilter.h
index 770a5565a..513896298 100644
--- a/src/lib/server/InputFilter.h
+++ b/src/lib/server/InputFilter.h
@@ -18,7 +18,6 @@
 
 #pragma once
 
-#include "base/String.h"
 #include "common/stdmap.h"
 #include "common/stdset.h"
 #include "deskflow/IPlatformScreen.h"
@@ -50,7 +49,7 @@ public:
     virtual ~Condition();
 
     virtual Condition *clone() const = 0;
-    virtual String format() const = 0;
+    virtual std::string format() const = 0;
 
     virtual EFilterStatus match(const Event &) = 0;
 
@@ -71,7 +70,7 @@ public:
 
     // Condition overrides
     virtual Condition *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual EFilterStatus match(const Event &);
     virtual void enablePrimary(PrimaryClient *);
     virtual void disablePrimary(PrimaryClient *);
@@ -96,7 +95,7 @@ public:
 
     // Condition overrides
     virtual Condition *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual EFilterStatus match(const Event &);
 
   private:
@@ -109,16 +108,16 @@ public:
   class ScreenConnectedCondition : public Condition
   {
   public:
-    ScreenConnectedCondition(IEventQueue *events, const String &screen);
+    ScreenConnectedCondition(IEventQueue *events, const std::string &screen);
     virtual ~ScreenConnectedCondition();
 
     // Condition overrides
     virtual Condition *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual EFilterStatus match(const Event &);
 
   private:
-    String m_screen;
+    std::string m_screen;
     IEventQueue *m_events;
   };
 
@@ -133,7 +132,7 @@ public:
     virtual ~Action();
 
     virtual Action *clone() const = 0;
-    virtual String format() const = 0;
+    virtual std::string format() const = 0;
 
     virtual void perform(const Event &) = 0;
   };
@@ -155,7 +154,7 @@ public:
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   private:
@@ -177,7 +176,7 @@ public:
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   private:
@@ -189,17 +188,17 @@ public:
   class SwitchToScreenAction : public Action
   {
   public:
-    SwitchToScreenAction(IEventQueue *events, const String &screen);
+    SwitchToScreenAction(IEventQueue *events, const std::string &screen);
 
-    String getScreen() const;
+    std::string getScreen() const;
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   private:
-    String m_screen;
+    std::string m_screen;
     IEventQueue *m_events;
   };
 
@@ -213,7 +212,7 @@ public:
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   private:
@@ -233,19 +232,19 @@ public:
     };
 
     KeyboardBroadcastAction(IEventQueue *events, Mode = kToggle);
-    KeyboardBroadcastAction(IEventQueue *events, Mode, const std::set<String> &screens);
+    KeyboardBroadcastAction(IEventQueue *events, Mode, const std::set<std::string> &screens);
 
     Mode getMode() const;
-    std::set<String> getScreens() const;
+    std::set<std::string> getScreens() const;
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   private:
     Mode m_mode;
-    String m_screens;
+    std::string m_screens;
     IEventQueue *m_events;
   };
 
@@ -267,7 +266,7 @@ public:
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   protected:
@@ -296,7 +295,7 @@ public:
 
     // Action overrides
     virtual Action *clone() const;
-    virtual String format() const;
+    virtual std::string format() const;
     virtual void perform(const Event &);
 
   protected:
@@ -338,7 +337,7 @@ public:
     bool handleEvent(const Event &);
 
     // convert rule to a string
-    String format() const;
+    std::string format() const;
 
     // get the rule's condition
     const Condition *getCondition() const;
@@ -392,7 +391,7 @@ public:
   virtual void setPrimaryClient(PrimaryClient *client);
 
   // convert rules to a string
-  String format(const String &linePrefix) const;
+  std::string format(const std::string &linePrefix) const;
 
   // get number of rules
   UInt32 getNumRules() const;
diff --git a/src/lib/server/PrimaryClient.cpp b/src/lib/server/PrimaryClient.cpp
index a7024daec..4e3727329 100644
--- a/src/lib/server/PrimaryClient.cpp
+++ b/src/lib/server/PrimaryClient.cpp
@@ -26,7 +26,7 @@
 // PrimaryClient
 //
 
-PrimaryClient::PrimaryClient(const String &name, deskflow::Screen *screen)
+PrimaryClient::PrimaryClient(const std::string &name, deskflow::Screen *screen)
     : BaseClientProxy(name),
       m_screen(screen),
       m_fakeInputCount(0)
@@ -161,7 +161,7 @@ void PrimaryClient::setClipboardDirty(ClipboardID id, bool dirty)
   m_clipboardDirty[id] = dirty;
 }
 
-void PrimaryClient::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const String &)
+void PrimaryClient::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, const std::string &)
 {
   if (m_fakeInputCount > 0) {
     // XXX -- don't forward keystrokes to primary screen for now
@@ -172,7 +172,7 @@ void PrimaryClient::keyDown(KeyID key, KeyModifierMask mask, KeyButton button, c
   }
 }
 
-void PrimaryClient::keyRepeat(KeyID, KeyModifierMask, SInt32, KeyButton, const String &)
+void PrimaryClient::keyRepeat(KeyID, KeyModifierMask, SInt32, KeyButton, const std::string &)
 {
   // ignore
 }
@@ -228,12 +228,12 @@ void PrimaryClient::fileChunkSending(UInt8 mark, char *data, size_t dataSize)
   // ignore
 }
 
-String PrimaryClient::getSecureInputApp() const
+std::string PrimaryClient::getSecureInputApp() const
 {
   return m_screen->getSecureInputApp();
 }
 
-void PrimaryClient::secureInputNotification(const String &app) const
+void PrimaryClient::secureInputNotification(const std::string &app) const
 {
   if (app != "unknown") {
     AppUtil::instance().showNotification(
diff --git a/src/lib/server/PrimaryClient.h b/src/lib/server/PrimaryClient.h
index dfab74c7f..10b2406ea 100644
--- a/src/lib/server/PrimaryClient.h
+++ b/src/lib/server/PrimaryClient.h
@@ -37,7 +37,7 @@ public:
   /*!
   \c name is the name of the server and \p screen is primary screen.
   */
-  PrimaryClient(const String &name, deskflow::Screen *screen);
+  PrimaryClient(const std::string &name, deskflow::Screen *screen);
   ~PrimaryClient();
 
 #ifdef TEST_ENV
@@ -132,8 +132,8 @@ public:
   void setClipboard(ClipboardID, const IClipboard *) override;
   void grabClipboard(ClipboardID) override;
   void setClipboardDirty(ClipboardID, bool) override;
-  void keyDown(KeyID, KeyModifierMask, KeyButton, const String &) override;
-  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const String &) override;
+  void keyDown(KeyID, KeyModifierMask, KeyButton, const std::string &) override;
+  void keyRepeat(KeyID, KeyModifierMask, SInt32 count, KeyButton, const std::string &) override;
   void keyUp(KeyID, KeyModifierMask, KeyButton) override;
   void mouseDown(ButtonID) override;
   void mouseUp(ButtonID) override;
@@ -145,8 +145,8 @@ public:
   void setOptions(const OptionsList &options) override;
   void sendDragInfo(UInt32 fileCount, const char *info, size_t size) override;
   void fileChunkSending(UInt8 mark, char *data, size_t dataSize) override;
-  String getSecureInputApp() const override;
-  void secureInputNotification(const String &app) const override;
+  std::string getSecureInputApp() const override;
+  void secureInputNotification(const std::string &app) const override;
 
   deskflow::IStream *getStream() const override
   {
diff --git a/src/lib/server/Server.cpp b/src/lib/server/Server.cpp
index 7d4c27583..6431a7931 100644
--- a/src/lib/server/Server.cpp
+++ b/src/lib/server/Server.cpp
@@ -99,7 +99,7 @@ Server::Server(
   assert(config.isScreen(primaryClient->getName()));
   assert(m_screen != NULL);
 
-  String primaryName = getName(primaryClient);
+  std::string primaryName = getName(primaryClient);
 
   // clear clipboards
   for (ClipboardID id = 0; id < kClipboardEnd; ++id) {
@@ -358,7 +358,7 @@ UInt32 Server::getNumClients() const
   return (SInt32)m_clients.size();
 }
 
-void Server::getClients(std::vector<String> &list) const
+void Server::getClients(std::vector<std::string> &list) const
 {
   list.clear();
   for (ClientList::const_iterator index = m_clients.begin(); index != m_clients.end(); ++index) {
@@ -366,9 +366,9 @@ void Server::getClients(std::vector<String> &list) const
   }
 }
 
-String Server::getName(const BaseClientProxy *client) const
+std::string Server::getName(const BaseClientProxy *client) const
 {
-  String name = m_config->getCanonicalName(client->getName());
+  std::string name = m_config->getCanonicalName(client->getName());
   if (name.empty()) {
     name = client->getName();
   }
@@ -506,7 +506,7 @@ void Server::switchScreen(BaseClientProxy *dst, SInt32 x, SInt32 y, bool forScre
 
 #if defined(__APPLE__)
     if (dst != m_primaryClient) {
-      String secureInputApplication = m_primaryClient->getSecureInputApp();
+      std::string secureInputApplication = m_primaryClient->getSecureInputApp();
       if (secureInputApplication != "") {
         // display notification on the server
         m_primaryClient->secureInputNotification(secureInputApplication);
@@ -612,7 +612,7 @@ BaseClientProxy *Server::getNeighbor(BaseClientProxy *src, EDirection dir, SInt3
   assert(src != NULL);
 
   // get source screen name
-  String srcName = getName(src);
+  std::string srcName = getName(src);
   assert(!srcName.empty());
   LOG((CLOG_DEBUG2 "find neighbor on %s of \"%s\"", Config::dirName(dir), srcName.c_str()));
 
@@ -622,7 +622,7 @@ BaseClientProxy *Server::getNeighbor(BaseClientProxy *src, EDirection dir, SInt3
   // search for the closest neighbor that exists in direction dir
   float tTmp;
   for (;;) {
-    String dstName(m_config->getNeighbor(srcName, dir, t, &tTmp));
+    std::string dstName(m_config->getNeighbor(srcName, dir, t, &tTmp));
 
     // if nothing in that direction then return NULL. if the
     // destination is the source then we can make no more
@@ -763,7 +763,7 @@ void Server::avoidJumpZone(BaseClientProxy *dst, EDirection dir, SInt32 &x, SInt
     return;
   }
 
-  const String dstName(getName(dst));
+  const std::string dstName(getName(dst));
   SInt32 dx, dy, dw, dh;
   dst->getShape(dx, dy, dw, dh);
   float t = mapToFraction(dst, dir, x, y);
@@ -1485,7 +1485,7 @@ void Server::onClipboardChanged(BaseClientProxy *sender, ClipboardID id, UInt32
   // get data
   sender->getClipboard(id, &clipboard.m_clipboard);
 
-  String data = clipboard.m_clipboard.marshall();
+  std::string data = clipboard.m_clipboard.marshall();
   if (data.size() > m_maximumClipboardSize * 1024) {
     LOG(
         (CLOG_NOTE "not updating clipboard because it's over the size limit "
@@ -1566,7 +1566,7 @@ void Server::onScreensaver(bool activated)
   }
 }
 
-void Server::onKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const String &lang, const char *screens)
+void Server::onKeyDown(KeyID id, KeyModifierMask mask, KeyButton button, const std::string &lang, const char *screens)
 {
   LOG((CLOG_DEBUG1 "onKeyDown id=%d mask=0x%04x button=0x%04x lang=%s", id, mask, button, lang.c_str()));
   assert(m_active != NULL);
@@ -1612,7 +1612,7 @@ void Server::onKeyUp(KeyID id, KeyModifierMask mask, KeyButton button, const cha
   }
 }
 
-void Server::onKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const String &lang)
+void Server::onKeyRepeat(KeyID id, KeyModifierMask mask, SInt32 count, KeyButton button, const std::string &lang)
 {
   LOG(
       (CLOG_DEBUG1 "onKeyRepeat id=%d mask=0x%04x count=%d button=0x%04x lang=\"%s\"", id, mask, count, button,
@@ -1651,7 +1651,7 @@ void Server::onMouseUp(ButtonID id)
 
   if (m_args.m_enableDragDrop) {
     if (!m_screen->isOnScreen()) {
-      String &file = m_screen->getDraggingFilename();
+      std::string &file = m_screen->getDraggingFilename();
       if (!file.empty()) {
         sendFileToClient(file.c_str());
       }
@@ -1765,7 +1765,7 @@ void Server::sendDragInfoThread(void *arg)
   BaseClientProxy *newScreen = static_cast<BaseClientProxy *>(arg);
 
   m_dragFileList.clear();
-  String &dragFileList = m_screen->getDraggingFilename();
+  std::string &dragFileList = m_screen->getDraggingFilename();
   if (!dragFileList.empty()) {
     DragInformation di;
     di.setFilename(dragFileList);
@@ -1791,7 +1791,7 @@ void Server::sendDragInfoThread(void *arg)
 
 void Server::sendDragInfo(BaseClientProxy *newScreen)
 {
-  String infoString;
+  std::string infoString;
   UInt32 fileCount = DragInformation::setupDragInfo(m_dragFileList, infoString);
 
   if (fileCount > 0) {
@@ -2018,7 +2018,7 @@ void Server::writeToDropDirThread(void *)
 
 bool Server::addClient(BaseClientProxy *client)
 {
-  String name = getName(client);
+  std::string name = getName(client);
   if (m_clients.count(name) != 0) {
     return false;
   }
@@ -2219,7 +2219,7 @@ Server::LockCursorToScreenInfo *Server::LockCursorToScreenInfo::alloc(State stat
 // Server::SwitchToScreenInfo
 //
 
-Server::SwitchToScreenInfo *Server::SwitchToScreenInfo::alloc(const String &screen)
+Server::SwitchToScreenInfo *Server::SwitchToScreenInfo::alloc(const std::string &screen)
 {
   SwitchToScreenInfo *info = (SwitchToScreenInfo *)malloc(sizeof(SwitchToScreenInfo) + screen.size());
   std::copy(screen.c_str(), screen.c_str() + screen.size() + 1, info->m_screen);
@@ -2249,7 +2249,7 @@ Server::KeyboardBroadcastInfo *Server::KeyboardBroadcastInfo::alloc(State state)
   return info;
 }
 
-Server::KeyboardBroadcastInfo *Server::KeyboardBroadcastInfo::alloc(State state, const String &screens)
+Server::KeyboardBroadcastInfo *Server::KeyboardBroadcastInfo::alloc(State state, const std::string &screens)
 {
   KeyboardBroadcastInfo *info = (KeyboardBroadcastInfo *)malloc(sizeof(KeyboardBroadcastInfo) + screens.size());
   info->m_state = state;
@@ -2291,7 +2291,7 @@ void Server::sendFileThread(void *data)
   m_sendFileThread.reset(nullptr);
 }
 
-void Server::dragInfoReceived(UInt32 fileNum, String content)
+void Server::dragInfoReceived(UInt32 fileNum, std::string content)
 {
   if (!m_args.m_enableDragDrop) {
     LOG((CLOG_DEBUG "drag drop not enabled, ignoring drag info."));
diff --git a/src/lib/server/Server.h b/src/lib/server/Server.h
index 9a7445420..363b91a17 100644
--- a/src/lib/server/Server.h
+++ b/src/lib/server/Server.h
@@ -76,7 +76,7 @@ public:
   class SwitchToScreenInfo
   {
   public:
-    static SwitchToScreenInfo *alloc(const String &screen);
+    static SwitchToScreenInfo *alloc(const std::string &screen);
 
   public:
     // this is a C-string;  this type is a variable size structure
@@ -97,12 +97,12 @@ public:
   class ScreenConnectedInfo
   {
   public:
-    ScreenConnectedInfo(String screen) : m_screen(screen)
+    ScreenConnectedInfo(std::string screen) : m_screen(screen)
     {
     }
 
   public:
-    String m_screen; // was char[1]
+    std::string m_screen; // was char[1]
   };
 
   //! Keyboard broadcast data
@@ -117,7 +117,7 @@ public:
     };
 
     static KeyboardBroadcastInfo *alloc(State state = kToggle);
-    static KeyboardBroadcastInfo *alloc(State state, const String &screens);
+    static KeyboardBroadcastInfo *alloc(State state, const std::string &screens);
 
   public:
     State m_state;
@@ -181,7 +181,7 @@ public:
   void sendFileToClient(const char *filename);
 
   //! Received dragging information from client
-  void dragInfoReceived(UInt32 fileNum, String content);
+  void dragInfoReceived(UInt32 fileNum, std::string content);
 
   //! Store ClientListener pointer
   void setListener(ClientListener *p)
@@ -209,7 +209,7 @@ public:
   /*!
   Set the \c list to the names of the currently connected clients.
   */
-  void getClients(std::vector<String> &list) const;
+  void getClients(std::vector<std::string> &list) const;
 
   //! Return true if recieved file size is valid
   bool isReceivedFileSizeValid();
@@ -221,7 +221,7 @@ public:
   }
 
   //! Return received file data
-  String &getReceivedFileData()
+  std::string &getReceivedFileData()
   {
     return m_receivedFileData;
   }
@@ -239,7 +239,7 @@ public:
 
 private:
   // get canonical name of client
-  String getName(const BaseClientProxy *) const;
+  std::string getName(const BaseClientProxy *) const;
 
   // get the sides of the primary screen that have neighbors
   UInt32 getActivePrimarySides() const;
@@ -367,9 +367,9 @@ private:
   // event processing
   void onClipboardChanged(BaseClientProxy *sender, ClipboardID id, UInt32 seqNum);
   void onScreensaver(bool activated);
-  void onKeyDown(KeyID, KeyModifierMask, KeyButton, const String &, const char *screens);
+  void onKeyDown(KeyID, KeyModifierMask, KeyButton, const std::string &, const char *screens);
   void onKeyUp(KeyID, KeyModifierMask, KeyButton, const char *screens);
-  void onKeyRepeat(KeyID, KeyModifierMask, SInt32, KeyButton, const String &);
+  void onKeyRepeat(KeyID, KeyModifierMask, SInt32, KeyButton, const std::string &);
   void onMouseDown(ButtonID);
   void onMouseUp(ButtonID);
   bool onMouseMovePrimary(SInt32 x, SInt32 y);
@@ -424,8 +424,8 @@ private:
 
   public:
     Clipboard m_clipboard;
-    String m_clipboardData;
-    String m_clipboardOwner;
+    std::string m_clipboardData;
+    std::string m_clipboardOwner;
     UInt32 m_clipboardSeqNum;
   };
 
@@ -436,7 +436,7 @@ private:
   PrimaryClient *m_primaryClient;
 
   // all clients (including the primary client) indexed by name
-  using ClientList = std::map<String, BaseClientProxy *>;
+  using ClientList = std::map<std::string, BaseClientProxy *>;
   using ClientSet = std::set<BaseClientProxy *>;
   ClientList m_clients;
   ClientSet m_clientSet;
@@ -503,7 +503,7 @@ private:
   // flag whether or not we have broadcasting enabled and the screens to
   // which we should send broadcasted keys.
   bool m_keyboardBroadcasting;
-  String m_keyboardBroadcastingScreens;
+  std::string m_keyboardBroadcastingScreens;
 
   // screen locking (former scroll lock)
   bool m_lockedToScreen;
@@ -516,12 +516,12 @@ private:
   // file transfer
   using AutoThread = std::unique_ptr<Thread>;
   size_t m_expectedFileSize;
-  String m_receivedFileData;
+  std::string m_receivedFileData;
   DragFileList m_dragFileList;
   DragFileList m_fakeDragFileList;
   AutoThread m_sendFileThread;
   AutoThread m_writeToDropDirThread;
-  String m_dragFileExt;
+  std::string m_dragFileExt;
   bool m_ignoreFileTransfer;
   bool m_disableLockToScreen;
   bool m_enableClipboard;
diff --git a/src/test/integtests/ipc/IpcTests.cpp b/src/test/integtests/ipc/IpcTests.cpp
index a29152e37..e695bf517 100644
--- a/src/test/integtests/ipc/IpcTests.cpp
+++ b/src/test/integtests/ipc/IpcTests.cpp
@@ -24,7 +24,6 @@
 #include "arch/Arch.h"
 #include "base/EventQueue.h"
 #include "base/Log.h"
-#include "base/String.h"
 #include "base/TMethodEventJob.h"
 #include "base/TMethodJob.h"
 #include "common/ipc.h"
@@ -57,8 +56,8 @@ public:
   bool m_connectToServer_helloMessageReceived;
   bool m_connectToServer_hasClientNode;
   IpcServer *m_connectToServer_server;
-  String m_sendMessageToServer_receivedString;
-  String m_sendMessageToClient_receivedString;
+  std::string m_sendMessageToServer_receivedString;
+  std::string m_sendMessageToClient_receivedString;
   IpcClient *m_sendMessageToServer_client;
   IpcServer *m_sendMessageToClient_server;
   TestEventQueue m_events;
diff --git a/src/test/integtests/net/NetworkTests.cpp b/src/test/integtests/net/NetworkTests.cpp
index 748933d8b..a53444ca2 100644
--- a/src/test/integtests/net/NetworkTests.cpp
+++ b/src/test/integtests/net/NetworkTests.cpp
@@ -437,7 +437,7 @@ void NetworkTests::sendToServer_mockFile_fileRecieveCompleted(
 
 void NetworkTests::sendMockData(void *eventTarget) {
   // send first message (file size)
-  String size = deskflow::string::sizeTypeToString(kMockDataSize);
+  std::string size = deskflow::string::sizeTypeToString(kMockDataSize);
   FileChunk *sizeMessage = FileChunk::start(size);
 
   m_events.addEvent(
diff --git a/src/test/integtests/platform/MSWindowsClipboardTests.cpp b/src/test/integtests/platform/MSWindowsClipboardTests.cpp
index 1af57a53c..7130534d4 100644
--- a/src/test/integtests/platform/MSWindowsClipboardTests.cpp
+++ b/src/test/integtests/platform/MSWindowsClipboardTests.cpp
@@ -89,7 +89,7 @@ TEST_F(MSWindowsClipboardTests, add_newValue_valueWasStored)
 
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
 
@@ -113,7 +113,7 @@ TEST_F(MSWindowsClipboardTests, add_replaceValue_valueWasReplaced)
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.add(IClipboard::kText, "maxivista sucks"); // haha, just kidding.
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("maxivista sucks", actual);
 }
 
@@ -200,7 +200,7 @@ TEST_F(MSWindowsClipboardTests, get_withNoFormats_returnsEmpty)
   clipboard.open(0);
   clipboard.empty();
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("", actual);
 }
@@ -212,7 +212,7 @@ TEST_F(MSWindowsClipboardTests, get_withFormatAdded_returnsExpected)
   clipboard.empty();
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("synergy rocks!", actual);
 }
diff --git a/src/test/integtests/platform/OSXClipboardTests.cpp b/src/test/integtests/platform/OSXClipboardTests.cpp
index 60f96413b..34f82953e 100644
--- a/src/test/integtests/platform/OSXClipboardTests.cpp
+++ b/src/test/integtests/platform/OSXClipboardTests.cpp
@@ -49,7 +49,7 @@ TEST(OSXClipboardTests, add_newValue_valueWasStored) {
 
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
 
@@ -60,7 +60,7 @@ TEST(OSXClipboardTests, add_replaceValue_valueWasReplaced) {
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.add(IClipboard::kText, "maxivista sucks"); // haha, just kidding.
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("maxivista sucks", actual);
 }
 
@@ -136,7 +136,7 @@ TEST(OSXClipboardTests, get_withNoFormats_returnsEmpty) {
   clipboard.open(0);
   clipboard.empty();
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("", actual);
 }
@@ -147,9 +147,9 @@ TEST(OSXClipboardTests, get_withFormatAdded_returnsExpected) {
   clipboard.empty();
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("synergy rocks!", actual);
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/test/integtests/platform/XWindowsClipboardTests.cpp b/src/test/integtests/platform/XWindowsClipboardTests.cpp
index d79509536..b3a424ca4 100644
--- a/src/test/integtests/platform/XWindowsClipboardTests.cpp
+++ b/src/test/integtests/platform/XWindowsClipboardTests.cpp
@@ -82,7 +82,7 @@ TEST_F(XWindowsClipboardTests, add_newValue_valueWasStored) {
 
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
 
@@ -92,7 +92,7 @@ TEST_F(XWindowsClipboardTests, add_replaceValue_valueWasReplaced) {
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.add(IClipboard::kText, "maxivista sucks"); // haha, just kidding.
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("maxivista sucks", actual);
 }
 
@@ -125,7 +125,7 @@ TEST_F(XWindowsClipboardTests, has_withNoFormats_returnsFalse) {
 TEST_F(XWindowsClipboardTests, get_withNoFormats_returnsEmpty) {
   XWindowsClipboard &clipboard = getClipboard();
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("", actual);
 }
@@ -134,7 +134,7 @@ TEST_F(XWindowsClipboardTests, get_withFormatAdded_returnsExpected) {
   XWindowsClipboard &clipboard = getClipboard();
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("synergy rocks!", actual);
 }
diff --git a/src/test/mock/deskflow/MockApp.h b/src/test/mock/deskflow/MockApp.h
index 49ae7ba96..6d5b9530f 100644
--- a/src/test/mock/deskflow/MockApp.h
+++ b/src/test/mock/deskflow/MockApp.h
@@ -32,7 +32,7 @@ public:
 
   MOCK_METHOD(void, help, (), (override));
   MOCK_METHOD(void, loadConfig, (), (override));
-  MOCK_METHOD(bool, loadConfig, (const String &), (override));
+  MOCK_METHOD(bool, loadConfig, (const std::string &), (override));
   MOCK_METHOD(const char *, daemonInfo, (), (const, override));
   MOCK_METHOD(const char *, daemonName, (), (const, override));
   MOCK_METHOD(void, parseArgs, (int, const char *const *), (override));
diff --git a/src/test/mock/deskflow/MockEventQueue.h b/src/test/mock/deskflow/MockEventQueue.h
index e3094bd27..9f47148fe 100644
--- a/src/test/mock/deskflow/MockEventQueue.h
+++ b/src/test/mock/deskflow/MockEventQueue.h
@@ -41,7 +41,7 @@ public:
   MOCK_METHOD(bool, dispatchEvent, (const Event &), (override));
   MOCK_METHOD(IEventJob *, getHandler, (Event::Type, void *), (const, override));
   MOCK_METHOD(void, deleteTimer, (EventQueueTimer *), (override));
-  MOCK_METHOD(Event::Type, getRegisteredType, (const String &), (const, override));
+  MOCK_METHOD(Event::Type, getRegisteredType, (const std::string &), (const, override));
   MOCK_METHOD(void *, getSystemTarget, (), (override));
   MOCK_METHOD(ClientEvents &, forClient, (), (override));
   MOCK_METHOD(IStreamEvents &, forIStream, (), (override));
diff --git a/src/test/mock/deskflow/MockKeyMap.h b/src/test/mock/deskflow/MockKeyMap.h
index 195e7366e..c22b89c4d 100644
--- a/src/test/mock/deskflow/MockKeyMap.h
+++ b/src/test/mock/deskflow/MockKeyMap.h
@@ -17,7 +17,6 @@
  */
 
 #pragma once
-#include "base/String.h"
 #include "deskflow/KeyMap.h"
 
 #include <gmock/gmock.h>
@@ -32,7 +31,7 @@ public:
   MOCK_METHOD(bool, isHalfDuplex, (KeyID, KeyButton), (const, override));
   MOCK_METHOD(
       const KeyMap::KeyItem *, mapKey,
-      (Keystrokes &, KeyID, SInt32, ModifierToKeys &, KeyModifierMask &, KeyModifierMask, bool, const String &),
+      (Keystrokes &, KeyID, SInt32, ModifierToKeys &, KeyModifierMask &, KeyModifierMask, bool, const std::string &),
       (const, override)
   );
 };
diff --git a/src/test/mock/server/MockConfig.h b/src/test/mock/server/MockConfig.h
index 95288bf95..5ed95e63a 100644
--- a/src/test/mock/server/MockConfig.h
+++ b/src/test/mock/server/MockConfig.h
@@ -30,5 +30,5 @@ public:
   {
   }
   MOCK_METHOD(InputFilter *, getInputFilter, (), (override));
-  MOCK_METHOD(bool, isScreen, (const String &), (const, override));
+  MOCK_METHOD(bool, isScreen, (const std::string &), (const, override));
 };
diff --git a/src/test/mock/server/MockPrimaryClient.h b/src/test/mock/server/MockPrimaryClient.h
index 67033471a..1297f6dde 100644
--- a/src/test/mock/server/MockPrimaryClient.h
+++ b/src/test/mock/server/MockPrimaryClient.h
@@ -19,7 +19,6 @@
 
 #define TEST_ENV
 
-#include "base/String.h"
 #include "server/PrimaryClient.h"
 
 #include <gmock/gmock.h>
diff --git a/src/test/unittests/base/StringTests.cpp b/src/test/unittests/base/StringTests.cpp
index b029fbf2d..14947cb8f 100644
--- a/src/test/unittests/base/StringTests.cpp
+++ b/src/test/unittests/base/StringTests.cpp
@@ -27,16 +27,16 @@ TEST(StringTests, format_formatWithArguments_formatedString)
   const char *arg1 = "answer";
   const char *arg2 = "42";
 
-  String result = string::format(format, arg1, arg2);
+  std::string result = string::format(format, arg1, arg2);
 
   EXPECT_EQ("%answer=42", result);
 }
 
 TEST(StringTests, findReplaceAll_inputString_replacedString)
 {
-  String subject = "foobar";
-  String find = "bar";
-  String replace = "baz";
+  std::string subject = "foobar";
+  std::string find = "bar";
+  std::string replace = "baz";
 
   string::findReplaceAll(subject, find, replace);
 
@@ -49,14 +49,14 @@ TEST(StringTests, sprintf_formatWithArgument_formatedString)
   const char *arg1 = "answer";
   int arg2 = 42;
 
-  String result = string::sprintf(format, arg1, arg2);
+  std::string result = string::sprintf(format, arg1, arg2);
 
   EXPECT_EQ("answer=42", result);
 }
 
 TEST(StringTests, toHex_plaintext_hexString)
 {
-  String subject = "foobar";
+  std::string subject = "foobar";
   int width = 2;
 
   string::toHex(subject, width);
@@ -66,7 +66,7 @@ TEST(StringTests, toHex_plaintext_hexString)
 
 TEST(StringTests, uppercase_lowercaseInput_uppercaseOutput)
 {
-  String subject = "12foo3BaR";
+  std::string subject = "12foo3BaR";
 
   string::uppercase(subject);
 
@@ -75,7 +75,7 @@ TEST(StringTests, uppercase_lowercaseInput_uppercaseOutput)
 
 TEST(StringTests, removeChar_inputString_removeAllSpecifiedCharactors)
 {
-  String subject = "foobar";
+  std::string subject = "foobar";
   const char c = 'o';
 
   string::removeChar(subject, c);
@@ -87,14 +87,14 @@ TEST(StringTests, intToString_inputInt_outputString)
 {
   size_t value = 123;
 
-  String number = string::sizeTypeToString(value);
+  std::string number = string::sizeTypeToString(value);
 
   EXPECT_EQ("123", number);
 }
 
 TEST(StringTests, stringToUint_inputString_outputInt)
 {
-  String number = "123";
+  std::string number = "123";
 
   size_t value = string::stringToSizeType(number);
 
@@ -103,9 +103,9 @@ TEST(StringTests, stringToUint_inputString_outputInt)
 
 TEST(StringTests, splitString_twoSeparator_returnThreeParts)
 {
-  String string = "stub1:stub2:stub3";
+  std::string string = "stub1:stub2:stub3";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(3, results.size());
   EXPECT_EQ("stub1", results[0]);
@@ -115,9 +115,9 @@ TEST(StringTests, splitString_twoSeparator_returnThreeParts)
 
 TEST(StringTests, splitString_oneSeparator_returnTwoParts)
 {
-  String string = "stub1:stub2";
+  std::string string = "stub1:stub2";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(2, results.size());
   EXPECT_EQ("stub1", results[0]);
@@ -126,9 +126,9 @@ TEST(StringTests, splitString_oneSeparator_returnTwoParts)
 
 TEST(StringTests, splitString_noSeparator_returnOriginalString)
 {
-  String string = "stub1";
+  std::string string = "stub1";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(1, results.size());
   EXPECT_EQ("stub1", results[0]);
@@ -136,18 +136,18 @@ TEST(StringTests, splitString_noSeparator_returnOriginalString)
 
 TEST(StringTests, splitString_emptyString_returnEmptyVector)
 {
-  String string;
+  std::string string;
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(0, results.size());
 }
 
 TEST(StringTests, splitString_tailSeparator_returnTwoParts)
 {
-  String string = "stub1:stub2:";
+  std::string string = "stub1:stub2:";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(2, results.size());
   EXPECT_EQ("stub1", results[0]);
@@ -156,9 +156,9 @@ TEST(StringTests, splitString_tailSeparator_returnTwoParts)
 
 TEST(StringTests, splitString_headSeparator_returnTwoParts)
 {
-  String string = ":stub1:stub2";
+  std::string string = ":stub1:stub2";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(2, results.size());
   EXPECT_EQ("stub1", results[0]);
@@ -167,9 +167,9 @@ TEST(StringTests, splitString_headSeparator_returnTwoParts)
 
 TEST(StringTests, splitString_headAndTailSeparators_returnTwoParts)
 {
-  String string = ":stub1:stub2:";
+  std::string string = ":stub1:stub2:";
 
-  std::vector<String> results = string::splitString(string, ':');
+  std::vector<std::string> results = string::splitString(string, ':');
 
   EXPECT_EQ(2, results.size());
   EXPECT_EQ("stub1", results[0]);
diff --git a/src/test/unittests/base/UnicodeTests.cpp b/src/test/unittests/base/UnicodeTests.cpp
index 2154a070c..2ff3948d8 100644
--- a/src/test/unittests/base/UnicodeTests.cpp
+++ b/src/test/unittests/base/UnicodeTests.cpp
@@ -23,7 +23,7 @@
 TEST(UnicodeTests, doUTF32ToUTF8_will_convert_simple_string)
 {
   bool errors;
-  auto result = Unicode::UTF32ToUTF8(String("h\0\0\0e\0\0\0l\0\0\0l\0\0\0o\0\0\0", 20), &errors);
+  auto result = Unicode::UTF32ToUTF8(std::string("h\0\0\0e\0\0\0l\0\0\0l\0\0\0o\0\0\0", 20), &errors);
   EXPECT_FALSE(errors);
   EXPECT_STREQ(result.c_str(), "hello");
 }
@@ -31,7 +31,7 @@ TEST(UnicodeTests, doUTF32ToUTF8_will_convert_simple_string)
 TEST(UnicodeTests, doUTF16ToUTF8_will_convert_simple_string)
 {
   bool errors;
-  auto result = Unicode::UTF16ToUTF8(String("h\0e\0l\0l\0o\0", 10), &errors);
+  auto result = Unicode::UTF16ToUTF8(std::string("h\0e\0l\0l\0o\0", 10), &errors);
   EXPECT_FALSE(errors);
   EXPECT_STREQ(result.c_str(), "hello");
 }
@@ -42,9 +42,9 @@ TEST(UnicodeTests, doUCS2ToUTF8_will_convert_simple_string_kUCS2)
   auto result = Unicode::textToUTF8("hello", &errors, IArchString::kUCS2);
   EXPECT_FALSE(errors);
 #ifdef _WIN32
-  EXPECT_EQ(result, String("hello", 5)); // mixed-platform expected result
+  EXPECT_EQ(result, std::string("hello", 5)); // mixed-platform expected result
 #else
-  EXPECT_EQ(result, String("h\0e\0l", 5)); // mixed-platform expected result
+  EXPECT_EQ(result, std::string("h\0e\0l", 5)); // mixed-platform expected result
 #endif // _WIN32
 }
 
@@ -53,5 +53,5 @@ TEST(UnicodeTests, doUCS2ToUTF8_will_convert_simple_string_any_platform)
   bool errors;
   auto result = Unicode::textToUTF8("hello", &errors);
   EXPECT_FALSE(errors);
-  EXPECT_EQ(result, String("hello", 5)); // mixed-platform expected result
+  EXPECT_EQ(result, std::string("hello", 5)); // mixed-platform expected result
 }
diff --git a/src/test/unittests/deskflow/ArgParserTests.cpp b/src/test/unittests/deskflow/ArgParserTests.cpp
index 243785f89..4cac71aed 100644
--- a/src/test/unittests/deskflow/ArgParserTests.cpp
+++ b/src/test/unittests/deskflow/ArgParserTests.cpp
@@ -63,7 +63,7 @@ TEST(ArgParserTests, isArg_missingArgs_returnFalse)
 
 TEST(ArgParserTests, searchDoubleQuotes_doubleQuotedArg_returnTrue)
 {
-  String command("\"stub\"");
+  std::string command("\"stub\"");
   size_t left = 0;
   size_t right = 0;
 
@@ -76,7 +76,7 @@ TEST(ArgParserTests, searchDoubleQuotes_doubleQuotedArg_returnTrue)
 
 TEST(ArgParserTests, searchDoubleQuotes_noDoubleQuotedArg_returnfalse)
 {
-  String command("stub");
+  std::string command("stub");
   size_t left = 0;
   size_t right = 0;
 
@@ -89,7 +89,7 @@ TEST(ArgParserTests, searchDoubleQuotes_noDoubleQuotedArg_returnfalse)
 
 TEST(ArgParserTests, searchDoubleQuotes_oneDoubleQuoteArg_returnfalse)
 {
-  String command("\"stub");
+  std::string command("\"stub");
   size_t left = 0;
   size_t right = 0;
 
@@ -102,8 +102,8 @@ TEST(ArgParserTests, searchDoubleQuotes_oneDoubleQuoteArg_returnfalse)
 
 TEST(ArgParserTests, splitCommandString_oneArg_returnArgv)
 {
-  String command("stub");
-  std::vector<String> argv;
+  std::string command("stub");
+  std::vector<std::string> argv;
 
   ArgParser::splitCommandString(command, argv);
 
@@ -113,8 +113,8 @@ TEST(ArgParserTests, splitCommandString_oneArg_returnArgv)
 
 TEST(ArgParserTests, splitCommandString_twoArgs_returnArgv)
 {
-  String command("stub1 stub2");
-  std::vector<String> argv;
+  std::string command("stub1 stub2");
+  std::vector<std::string> argv;
 
   ArgParser::splitCommandString(command, argv);
 
@@ -125,8 +125,8 @@ TEST(ArgParserTests, splitCommandString_twoArgs_returnArgv)
 
 TEST(ArgParserTests, splitCommandString_doubleQuotedArgs_returnArgv)
 {
-  String command("\"stub1\" stub2 \"stub3\"");
-  std::vector<String> argv;
+  std::string command("\"stub1\" stub2 \"stub3\"");
+  std::vector<std::string> argv;
 
   ArgParser::splitCommandString(command, argv);
 
@@ -138,8 +138,8 @@ TEST(ArgParserTests, splitCommandString_doubleQuotedArgs_returnArgv)
 
 TEST(ArgParserTests, splitCommandString_spaceDoubleQuotedArgs_returnArgv)
 {
-  String command("\"stub1\" stub2 \"stub3 space\"");
-  std::vector<String> argv;
+  std::string command("\"stub1\" stub2 \"stub3 space\"");
+  std::vector<std::string> argv;
 
   ArgParser::splitCommandString(command, argv);
 
@@ -151,15 +151,15 @@ TEST(ArgParserTests, splitCommandString_spaceDoubleQuotedArgs_returnArgv)
 
 TEST(ArgParserTests, getArgv_stringArray_return2DArray)
 {
-  std::vector<String> argArray;
+  std::vector<std::string> argArray;
   argArray.push_back("stub1");
   argArray.push_back("stub2");
   argArray.push_back("stub3 space");
   const char **argv = ArgParser::getArgv(argArray);
 
-  String row1(argv[0]);
-  String row2(argv[1]);
-  String row3(argv[2]);
+  std::string row1(argv[0]);
+  std::string row2(argv[1]);
+  std::string row3(argv[2]);
 
   EXPECT_EQ("stub1", row1);
   EXPECT_EQ("stub2", row2);
@@ -170,43 +170,43 @@ TEST(ArgParserTests, getArgv_stringArray_return2DArray)
 
 TEST(ArgParserTests, assembleCommand_stringArray_returnCommand)
 {
-  std::vector<String> argArray;
+  std::vector<std::string> argArray;
   argArray.push_back("stub1");
   argArray.push_back("stub2");
-  String command = ArgParser::assembleCommand(argArray);
+  std::string command = ArgParser::assembleCommand(argArray);
 
   EXPECT_EQ("stub1 stub2", command);
 }
 
 TEST(ArgParserTests, assembleCommand_ignoreSecondArg_returnCommand)
 {
-  std::vector<String> argArray;
+  std::vector<std::string> argArray;
   argArray.push_back("stub1");
   argArray.push_back("stub2");
-  String command = ArgParser::assembleCommand(argArray, "stub2");
+  std::string command = ArgParser::assembleCommand(argArray, "stub2");
 
   EXPECT_EQ("stub1", command);
 }
 
 TEST(ArgParserTests, assembleCommand_ignoreSecondArgWithOneParameter_returnCommand)
 {
-  std::vector<String> argArray;
+  std::vector<std::string> argArray;
   argArray.push_back("stub1");
   argArray.push_back("stub2");
   argArray.push_back("stub3");
   argArray.push_back("stub4");
-  String command = ArgParser::assembleCommand(argArray, "stub2", 1);
+  std::string command = ArgParser::assembleCommand(argArray, "stub2", 1);
 
   EXPECT_EQ("stub1 stub4", command);
 }
 
 TEST(ArgParserTests, assembleCommand_stringArrayWithSpace_returnCommand)
 {
-  std::vector<String> argArray;
+  std::vector<std::string> argArray;
   argArray.push_back("stub1 space");
   argArray.push_back("stub2");
   argArray.push_back("stub3 space");
-  String command = ArgParser::assembleCommand(argArray);
+  std::string command = ArgParser::assembleCommand(argArray);
 
   EXPECT_EQ("\"stub1 space\" stub2 \"stub3 space\"", command);
 }
diff --git a/src/test/unittests/deskflow/ClipboardChunkTests.cpp b/src/test/unittests/deskflow/ClipboardChunkTests.cpp
index 08eb204a5..f83617dfe 100644
--- a/src/test/unittests/deskflow/ClipboardChunkTests.cpp
+++ b/src/test/unittests/deskflow/ClipboardChunkTests.cpp
@@ -24,7 +24,7 @@ TEST(ClipboardChunkTests, start_formatStartChunk)
 {
   ClipboardID id = 0;
   UInt32 sequence = 0;
-  String mockDataSize("10");
+  std::string mockDataSize("10");
   ClipboardChunk *chunk = ClipboardChunk::start(id, sequence, mockDataSize);
   UInt32 temp_m_chunk;
   memcpy(&temp_m_chunk, &(chunk->m_chunk[1]), 4);
@@ -43,7 +43,7 @@ TEST(ClipboardChunkTests, data_formatDataChunk)
 {
   ClipboardID id = 0;
   UInt32 sequence = 1;
-  String mockData("mock data");
+  std::string mockData("mock data");
   ClipboardChunk *chunk = ClipboardChunk::data(id, sequence, mockData);
 
   EXPECT_EQ(id, chunk->m_chunk[0]);
diff --git a/src/test/unittests/deskflow/ClipboardTests.cpp b/src/test/unittests/deskflow/ClipboardTests.cpp
index 15230f2ff..02037f0d2 100644
--- a/src/test/unittests/deskflow/ClipboardTests.cpp
+++ b/src/test/unittests/deskflow/ClipboardTests.cpp
@@ -49,7 +49,7 @@ TEST(ClipboardTests, add_newValue_valueWasStored)
 
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
 
@@ -61,7 +61,7 @@ TEST(ClipboardTests, add_replaceValue_valueWasReplaced)
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.add(IClipboard::kText, "maxivista sucks"); // haha, just kidding.
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("maxivista sucks", actual);
 }
 
@@ -140,7 +140,7 @@ TEST(ClipboardTests, get_withNoFormats_returnsEmpty)
   Clipboard clipboard;
   clipboard.open(0);
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("", actual);
 }
@@ -151,7 +151,7 @@ TEST(ClipboardTests, get_withFormatAdded_returnsExpected)
   clipboard.open(0);
   clipboard.add(IClipboard::kText, "synergy rocks!");
 
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
 
   EXPECT_EQ("synergy rocks!", actual);
 }
@@ -160,7 +160,7 @@ TEST(ClipboardTests, marshall_addNotCalled_firstCharIsZero)
 {
   Clipboard clipboard;
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // seems to return "\0\0\0\0" but EXPECT_EQ can't assert this,
   // so instead, just assert that first char is '\0'.
@@ -174,7 +174,7 @@ TEST(ClipboardTests, marshall_withTextAdded_typeCharIsText)
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // string contains other data, but 8th char should be kText.
   EXPECT_EQ(IClipboard::kText, (int)actual[7]);
@@ -187,7 +187,7 @@ TEST(ClipboardTests, marshall_withTextAdded_lastSizeCharIs14)
   clipboard.add(IClipboard::kText, "synergy rocks!"); // 14 chars
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   EXPECT_EQ(14, (int)actual[11]);
 }
@@ -198,7 +198,7 @@ TEST(ClipboardTests, marshall_withTextAdded_lastSizeCharIs14)
 TEST(ClipboardTests, marshall_withTextSize285_sizeCharsValid)
 {
   // 285 chars
-  String data;
+  std::string data;
   data.append("Synergy is Free and Open Source Software that lets you ");
   data.append("easily share your mouse and keyboard between multiple ");
   data.append("computers, where each computer has it's own display. No ");
@@ -210,7 +210,7 @@ TEST(ClipboardTests, marshall_withTextSize285_sizeCharsValid)
   clipboard.add(IClipboard::kText, data);
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // 4 asserts here, but that's ok because we're really just asserting 1
   // thing. the 32-bit size value is split into 4 chars. if the size is 285
@@ -232,7 +232,7 @@ TEST(ClipboardTests, marshall_withHtmlAdded_typeCharIsHtml)
   clipboard.add(IClipboard::kHTML, "html sucks");
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // string contains other data, but 8th char should be kHTML.
   EXPECT_EQ(IClipboard::kHTML, (int)actual[7]);
@@ -246,7 +246,7 @@ TEST(ClipboardTests, marshall_withHtmlAndText_has2Formats)
   clipboard.add(IClipboard::kHTML, "html sucks");
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // the number of formats is stored inside the first 4 chars.
   // the writeUInt32 function right-aligns numbers in 4 chars,
@@ -263,7 +263,7 @@ TEST(ClipboardTests, marshall_withTextAdded_endsWithAdded)
   clipboard.add(IClipboard::kText, "synergy rocks!");
   clipboard.close();
 
-  String actual = clipboard.marshall();
+  std::string actual = clipboard.marshall();
 
   // string contains other data, but should end in the string we added.
   EXPECT_EQ("synergy rocks!", actual.substr(12));
@@ -273,7 +273,7 @@ TEST(ClipboardTests, unmarshall_emptyData_hasTextIsFalse)
 {
   Clipboard clipboard;
 
-  String data;
+  std::string data;
   data += (char)0;
   data += (char)0;
   data += (char)0;
@@ -291,14 +291,14 @@ TEST(ClipboardTests, unmarshall_withTextSize285_getTextIsValid)
   Clipboard clipboard;
 
   // 285 chars
-  String text;
+  std::string text;
   text.append("Synergy is Free and Open Source Software that lets you ");
   text.append("easily share your mouse and keyboard between multiple ");
   text.append("computers, where each computer has it's own display. No ");
   text.append("special hardware is required, all you need is a local area ");
   text.append("network. Synergy is supported on Windows, Mac OS X and Linux.");
 
-  String data;
+  std::string data;
   data += (char)0;
   data += (char)0;
   data += (char)0;
@@ -316,14 +316,14 @@ TEST(ClipboardTests, unmarshall_withTextSize285_getTextIsValid)
   clipboard.unmarshall(data, 0);
 
   clipboard.open(0);
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ(text, actual);
 }
 
 TEST(ClipboardTests, unmarshall_withTextAndHtml_getTextIsValid)
 {
   Clipboard clipboard;
-  String data;
+  std::string data;
   data += (char)0;
   data += (char)0;
   data += (char)0;
@@ -350,14 +350,14 @@ TEST(ClipboardTests, unmarshall_withTextAndHtml_getTextIsValid)
   clipboard.unmarshall(data, 0);
 
   clipboard.open(0);
-  String actual = clipboard.get(IClipboard::kText);
+  std::string actual = clipboard.get(IClipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
 
 TEST(ClipboardTests, unmarshall_withTextAndHtml_getHtmlIsValid)
 {
   Clipboard clipboard;
-  String data;
+  std::string data;
   data += (char)0;
   data += (char)0;
   data += (char)0;
@@ -384,7 +384,7 @@ TEST(ClipboardTests, unmarshall_withTextAndHtml_getHtmlIsValid)
   clipboard.unmarshall(data, 0);
 
   clipboard.open(0);
-  String actual = clipboard.get(IClipboard::kHTML);
+  std::string actual = clipboard.get(IClipboard::kHTML);
   EXPECT_EQ("html sucks", actual);
 }
 
@@ -399,6 +399,6 @@ TEST(ClipboardTests, copy_withSingleText_clipboardsAreEqual)
   Clipboard::copy(&clipboard2, &clipboard1);
 
   clipboard2.open(0);
-  String actual = clipboard2.get(Clipboard::kText);
+  std::string actual = clipboard2.get(Clipboard::kText);
   EXPECT_EQ("synergy rocks!", actual);
 }
diff --git a/src/test/unittests/deskflow/GenericArgsParsingTests.cpp b/src/test/unittests/deskflow/GenericArgsParsingTests.cpp
index 8eb3e38b0..648d20fdc 100644
--- a/src/test/unittests/deskflow/GenericArgsParsingTests.cpp
+++ b/src/test/unittests/deskflow/GenericArgsParsingTests.cpp
@@ -66,7 +66,7 @@ TEST_F(GenericArgsParsingTests, parseGenericArgs_logLevelCmd_setLogLevel)
   const char *kLogLevelCmd[argc] = {"stub", "--debug", "DEBUG"};
 
   m_argParser->parseGenericArgs(argc, kLogLevelCmd, i);
-  String logFilter(argsBase.m_logFilter);
+  std::string logFilter(argsBase.m_logFilter);
 
   EXPECT_EQ("DEBUG", logFilter);
   EXPECT_EQ(2, i);
@@ -79,7 +79,7 @@ TEST_F(GenericArgsParsingTests, parseGenericArgs_logFileCmd_saveLogFilename)
   const char *kLogFileCmd[argc] = {"stub", "--log", "mock_filename"};
 
   m_argParser->parseGenericArgs(argc, kLogFileCmd, i);
-  String logFile(argsBase.m_logFile);
+  std::string logFile(argsBase.m_logFile);
 
   EXPECT_EQ("mock_filename", logFile);
   EXPECT_EQ(2, i);
@@ -92,7 +92,7 @@ TEST_F(GenericArgsParsingTests, parseGenericArgs_logFileCmdWithSpace_saveLogFile
   const char *kLogFileCmdWithSpace[argc] = {"stub", "--log", "mo ck_filename"};
 
   m_argParser->parseGenericArgs(argc, kLogFileCmdWithSpace, i);
-  String logFile(argsBase.m_logFile);
+  std::string logFile(argsBase.m_logFile);
 
   EXPECT_EQ("mo ck_filename", logFile);
   EXPECT_EQ(2, i);
diff --git a/src/test/unittests/deskflow/KeyStateTests.cpp b/src/test/unittests/deskflow/KeyStateTests.cpp
index 122a6af7f..602fd6534 100644
--- a/src/test/unittests/deskflow/KeyStateTests.cpp
+++ b/src/test/unittests/deskflow/KeyStateTests.cpp
@@ -36,7 +36,7 @@ void assertMaskIsOne(ForeachKeyCallback cb, void *userData);
 
 const deskflow::KeyMap::KeyItem *stubMapKey(
     deskflow::KeyMap::Keystrokes &keys, KeyID id, SInt32 group, deskflow::KeyMap::ModifierToKeys &activeModifiers,
-    KeyModifierMask &currentState, KeyModifierMask desiredMask, bool isAutoRepeat, const String &lang
+    KeyModifierMask &currentState, KeyModifierMask desiredMask, bool isAutoRepeat, const std::string &lang
 );
 
 deskflow::KeyMap::Keystroke s_stubKeystroke(1, false, false);
@@ -484,7 +484,7 @@ void assertMaskIsOne(ForeachKeyCallback cb, void *userData)
 }
 
 const deskflow::KeyMap::KeyItem *
-stubMapKey(deskflow::KeyMap::Keystrokes &keys, KeyID, SInt32, deskflow::KeyMap::ModifierToKeys &, KeyModifierMask &, KeyModifierMask, bool, const String &)
+stubMapKey(deskflow::KeyMap::Keystrokes &keys, KeyID, SInt32, deskflow::KeyMap::ModifierToKeys &, KeyModifierMask &, KeyModifierMask, bool, const std::string &)
 {
   keys.push_back(s_stubKeystroke);
   return &s_stubKeyItem;
diff --git a/src/test/unittests/deskflow/ProtocolUtilTests.cpp b/src/test/unittests/deskflow/ProtocolUtilTests.cpp
index 415956065..21ead8bac 100644
--- a/src/test/unittests/deskflow/ProtocolUtilTests.cpp
+++ b/src/test/unittests/deskflow/ProtocolUtilTests.cpp
@@ -506,7 +506,7 @@ INSTANTIATE_TEST_SUITE_P(WriteIntVectorTest, WriteIntVectorTest,
                                            std::make_tuple("%4I", 4)));
 
 TEST_F(ProtocolUtilTests, write_string_test) {
-  const String Expected = "Expected";
+  const std::string Expected = "Expected";
   const std::vector<UInt8> ExpectedVector = {'E', 'x', 'p', 'e',
                                              'c', 't', 'e', 'd'};
   EXPECT_CALL(stream, write(EqVoidVectorInt1byte(ExpectedVector),
diff --git a/src/test/unittests/deskflow/X11LayoutParserTests.cpp b/src/test/unittests/deskflow/X11LayoutParserTests.cpp
index 6b58f242f..427328f46 100644
--- a/src/test/unittests/deskflow/X11LayoutParserTests.cpp
+++ b/src/test/unittests/deskflow/X11LayoutParserTests.cpp
@@ -127,7 +127,7 @@ void createTestFiles()
 TEST(X11LayoutsParsingTests, xmlCorrectParsingTest)
 {
   createTestFiles();
-  std::vector<String> expectedResult = {"en", "ru"};
+  std::vector<std::string> expectedResult = {"en", "ru"};
   auto parsedResult = X11LayoutsParser::getX11LanguageList(testDir + "/correctEvdev.xml");
 
   EXPECT_EQ(parsedResult, parsedResult);
@@ -141,7 +141,7 @@ TEST(X11LayoutsParsingTests, xmlParsingMissedEvdevFileTest)
 
 TEST(X11LayoutsParsingTests, xmlParsingIncorrectEvdevFileTest)
 {
-  std::vector<String> parsedResult;
+  std::vector<std::string> parsedResult;
   parsedResult = X11LayoutsParser::getX11LanguageList(testDir + "/incorrectEvdev1.xml");
   EXPECT_TRUE(parsedResult.empty());
   parsedResult = X11LayoutsParser::getX11LanguageList(testDir + "/incorrectEvdev2.xml");
diff --git a/src/test/unittests/deskflow/languages/LanguageManagerTests.cpp b/src/test/unittests/deskflow/languages/LanguageManagerTests.cpp
index b7448cb26..0196caa38 100644
--- a/src/test/unittests/deskflow/languages/LanguageManagerTests.cpp
+++ b/src/test/unittests/deskflow/languages/LanguageManagerTests.cpp
@@ -27,13 +27,13 @@ TEST(LanguageManager, RemoteLanguagesTest)
   manager.setRemoteLanguages(remoteLanguages);
   EXPECT_EQ((std::vector<std::string>{"ru", "en", "uk"}), manager.getRemoteLanguages());
 
-  manager.setRemoteLanguages(String());
+  manager.setRemoteLanguages(std::string());
   EXPECT_TRUE(manager.getRemoteLanguages().empty());
 }
 
 TEST(LanguageManager, LocalLanguagesTest)
 {
-  std::vector<String> localLanguages = {"ru", "en", "uk"};
+  std::vector<std::string> localLanguages = {"ru", "en", "uk"};
   deskflow::languages::LanguageManager manager(localLanguages);
 
   EXPECT_EQ((std::vector<std::string>{"ru", "en", "uk"}), manager.getLocalLanguages());
@@ -41,8 +41,8 @@ TEST(LanguageManager, LocalLanguagesTest)
 
 TEST(LanguageManager, MissedLanguagesTest)
 {
-  String remoteLanguages = "ruenuk";
-  std::vector<String> localLanguages = {"en"};
+  std::string remoteLanguages = "ruenuk";
+  std::vector<std::string> localLanguages = {"en"};
   deskflow::languages::LanguageManager manager(localLanguages);
 
   manager.setRemoteLanguages(remoteLanguages);
@@ -51,7 +51,7 @@ TEST(LanguageManager, MissedLanguagesTest)
 
 TEST(LanguageManager, SerializeLocalLanguagesTest)
 {
-  std::vector<String> localLanguages = {"ru", "en", "uk"};
+  std::vector<std::string> localLanguages = {"ru", "en", "uk"};
   deskflow::languages::LanguageManager manager(localLanguages);
 
   EXPECT_EQ("ruenuk", manager.getSerializedLocalLanguages());
@@ -59,7 +59,7 @@ TEST(LanguageManager, SerializeLocalLanguagesTest)
 
 TEST(LanguageManager, LanguageInstalledTest)
 {
-  std::vector<String> localLanguages = {"ru", "en", "uk"};
+  std::vector<std::string> localLanguages = {"ru", "en", "uk"};
   deskflow::languages::LanguageManager manager(localLanguages);
 
   EXPECT_FALSE(manager.isLanguageInstalled("us"));
diff --git a/src/test/unittests/ipc/IpcLogOutputterTests.cpp b/src/test/unittests/ipc/IpcLogOutputterTests.cpp
index 0bcbd7c2f..e35bab660 100644
--- a/src/test/unittests/ipc/IpcLogOutputterTests.cpp
+++ b/src/test/unittests/ipc/IpcLogOutputterTests.cpp
@@ -43,7 +43,7 @@ using namespace deskflow;
 // TODO Fix the IPC Tests for windows, see #6709
 //  Tests disabled due to gtest/gmock update causing build problems
 //  Decision to disable tests and create issue instead due to time constraints
-// inline const Matcher<const IpcMessage&> IpcLogLineMessageEq(const String& s)
+// inline const Matcher<const IpcMessage&> IpcLogLineMessageEq(const std::string& s)
 // {
 //     const Matcher<const IpcLogLineMessage&> m(
 //         Property(&IpcLogLineMessage::logLine, StrEq(s)));
diff --git a/src/test/unittests/server/ConfigTests.cpp b/src/test/unittests/server/ConfigTests.cpp
index 3d461b477..e791c09c4 100644
--- a/src/test/unittests/server/ConfigTests.cpp
+++ b/src/test/unittests/server/ConfigTests.cpp
@@ -26,7 +26,7 @@
 class OnlySystemFilter : public InputFilter::Condition {
 public:
   Condition *clone() const override { return new OnlySystemFilter(); }
-  String format() const override { return ""; }
+  std::string format() const override { return ""; }
 
   InputFilter::EFilterStatus match(const Event &ev) override {
     return ev.getType() == Event::kSystem ? InputFilter::kActivate
@@ -92,25 +92,25 @@ TEST(ServerConfigTests,
 
 TEST(NetworkAddress, hostname_valid_parsing) {
   const int validPort = 24900;
-  const String portStr = std::to_string(validPort);
+  const std::string portStr = std::to_string(validPort);
 
   // list of test cases. 1 param - hostname for parsing, 2 param - port, 3 param
   // - expected hostname
-  const std::initializer_list<std::tuple<String, int, String>> validTestCases = {
-      std::make_tuple(String("127.0.0.1"), validPort, "127.0.0.1"),
-      std::make_tuple(String("127.0.0.1:") + portStr, 0, "127.0.0.1"),
-      std::make_tuple(String("localhost"), validPort, "localhost"),
-      std::make_tuple(String("localhost:") + portStr, 0, "localhost"),
-      std::make_tuple(String(""), validPort, ""),
-      std::make_tuple(String(":") + portStr, 0, ""),
+  const std::initializer_list<std::tuple<std::string, int, std::string>> validTestCases = {
+      std::make_tuple(std::string("127.0.0.1"), validPort, "127.0.0.1"),
+      std::make_tuple(std::string("127.0.0.1:") + portStr, 0, "127.0.0.1"),
+      std::make_tuple(std::string("localhost"), validPort, "localhost"),
+      std::make_tuple(std::string("localhost:") + portStr, 0, "localhost"),
+      std::make_tuple(std::string(""), validPort, ""),
+      std::make_tuple(std::string(":") + portStr, 0, ""),
       // Temporary disabled tests for ipv6
-      // std::make_tuple(String("[::1]:") + portStr, 0,         "::1"),
-      // std::make_tuple(String("[fe80::a156:9f36:793:7bfb%14]:") + portStr,
+      // std::make_tuple(std::string("[::1]:") + portStr, 0,         "::1"),
+      // std::make_tuple(std::string("[fe80::a156:9f36:793:7bfb%14]:") + portStr,
       // 0,         "fe80::a156:9f36:793:7bfb%14"),
-      // std::make_tuple(String("::1"), validPort, "::1"),
-      // std::make_tuple(String("fe80::a156:9f36:793:7bfb%14"), validPort,
+      // std::make_tuple(std::string("::1"), validPort, "::1"),
+      // std::make_tuple(std::string("fe80::a156:9f36:793:7bfb%14"), validPort,
       // "fe80::a156:9f36:793:7bfb%14"),
-      // std::make_tuple(String("fe80:0000:0000:0000:a156:9f36:793:7bfb%14"),
+      // std::make_tuple(std::string("fe80:0000:0000:0000:a156:9f36:793:7bfb%14"),
       // validPort, "fe80:0000:0000:0000:a156:9f36:793:7bfb%14"),
   };
 
@@ -124,7 +124,7 @@ TEST(NetworkAddress, hostname_valid_parsing) {
   }
 
   // list of non valid hostnames
-  const std::initializer_list<String> nonValidTestCases = {
+  const std::initializer_list<std::string> nonValidTestCases = {
       ":nonValidPort", ":",
       // Temporary disabled tests for ipv6
       //"[::1]:",