Index: common/CompilerDetect.h
===================================================================
--- common/CompilerDetect.h	(revision 14145)
+++ common/CompilerDetect.h	(working copy)
@@ -51,8 +51,8 @@
 #define MPT_GCC_AT_LEAST(major,minor,patch)          (MPT_COMPILER_GCC_VERSION >= MPT_COMPILER_MAKE_VERSION3((major),(minor),(patch)))
 #define MPT_GCC_BEFORE(major,minor,patch)            (MPT_COMPILER_GCC_VERSION <  MPT_COMPILER_MAKE_VERSION3((major),(minor),(patch)))
 
-#if MPT_GCC_BEFORE(8,1,0)
-#error "GCC version 8.1 required"
+#if MPT_GCC_BEFORE(9,1,0)
+#error "GCC version 9.1 required"
 #endif
 
 #elif defined(_MSC_VER)
Index: libopenmpt/dox/changelog.md
===================================================================
--- libopenmpt/dox/changelog.md	(revision 14145)
+++ libopenmpt/dox/changelog.md	(working copy)
@@ -23,10 +23,12 @@
     `EMSCRIPTEN_TARGET=all` which provides WebAssembly as well as fallback to
     JavaScript in a single build.
 
+ *  [**Regression**] Full C++17 support, including `std::filesystem`, is now
+    required to build libopenmpt.
  *  [**Regression**] `Makefile` `CONFIG=emscripten` does not support
     `EMSCRIPTEN_TARGET=asmjs` or `EMSCRIPTEN_TARGET=asmjs128m` any more because
     support has been removed from current Emscripten versions.
- *  [**Regression**] Support for GCC 7 has been removed.
+ *  [**Regression**] Support for GCC 7, 8 has been removed.
  *  [**Regression**] Support for Clang 5, 6 has been removed.
  *  [**Regression**] Support for Emscripten versions older than 1.39.7 has been
     removed.
Index: libopenmpt/dox/dependencies.md
===================================================================
--- libopenmpt/dox/dependencies.md	(revision 14145)
+++ libopenmpt/dox/dependencies.md	(working copy)
@@ -11,13 +11,13 @@
  *  Supported compilers for building libopenmpt:
      *  **Microsoft Visual Studio 2017** or higher, running on a x86-64 build
         system (other target systems are supported)
-     *  **GCC 8.1** or higher
+     *  **GCC 9.1** or higher
      *  **Clang 7** or higher
-     *  **MinGW-W64 8.1** or higher (it is recommended to preferably use
+     *  **MinGW-W64 9.1** or higher (it is recommended to preferably use
         posix threading model as opposed to win32 threading model, or at least
         have mingw-std-threads available otherwise)
      *  **emscripten 1.39.1** or higher
-     *  **DJGPP GCC 8.1** or higher
+     *  **DJGPP GCC 9.1** or higher
      *  any other **C++17 compliant** compiler
         
         libopenmpt makes the following assumptions about the C++ implementation
@@ -73,10 +73,10 @@
  *  Supported compilers for building openmpt123:
      *  **Microsoft Visual Studio 2017** or higher, running on a x86-64 build
         system (other target systems are supported)
-     *  **GCC 8.1** or higher
+     *  **GCC 9.1** or higher
      *  **Clang 7** or higher
-     *  **MinGW-W64 8.1** or higher
-     *  **DJGPP GCC 8.1** or higher
+     *  **MinGW-W64 9.1** or higher
+     *  **DJGPP GCC 9.1** or higher
      *  any **C++17 compliant** compiler
  *  Live sound output requires one of:
      *  **PulseAudio**