diff --git a/src/lib/base/Unicode.cpp b/src/lib/base/Unicode.cpp
index 47dacd9a3..18215e8c2 100644
--- a/src/lib/base/Unicode.cpp
+++ b/src/lib/base/Unicode.cpp
@@ -113,29 +113,6 @@ std::string Unicode::UTF8ToUCS2(const std::string &src, bool *errors)
   return dst;
 }
 
-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
-  auto n = (uint32_t)src.size();
-  std::string dst;
-  dst.reserve(4 * n);
-
-  // convert each character
-  const auto *data = reinterpret_cast<const uint8_t *>(src.c_str());
-  while (n > 0) {
-    uint32_t c = fromUTF8(data, n);
-    if (c == s_invalid) {
-      c = s_replacement;
-    }
-    dst.append(reinterpret_cast<const char *>(&c), 4);
-  }
-
-  return dst;
-}
-
 std::string Unicode::UTF8ToUTF16(const std::string &src, bool *errors)
 {
   // default to success
diff --git a/src/lib/base/Unicode.h b/src/lib/base/Unicode.h
index 43b37778d..212cdd0a0 100644
--- a/src/lib/base/Unicode.h
+++ b/src/lib/base/Unicode.h
@@ -36,14 +36,6 @@ public:
   */
   static std::string UTF8ToUCS2(const std::string &, bool *errors = nullptr);
 
-  //! Convert from UTF-8 to UCS-4 encoding
-  /*!
-  Convert from UTF-8 to UCS-4.  If errors is not nullptr then *errors
-  is set to true iff any character could not be encoded in UCS-4.
-  Decoding errors do not set *errors.
-  */
-  static std::string UTF8ToUCS4(const std::string &, bool *errors = nullptr);
-
   //! Convert from UTF-8 to UTF-16 encoding
   /*!
   Convert from UTF-8 to UTF-16.  If errors is not nullptr then *errors