Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -163,6 +163,13 @@
 - The presence of __attribute__((availability(...))) on a declaration no longer
   implies default visibility for that declaration on macOS.
 
+- Clang now supports configuration files. These are collections of driver
+  options, which can be applied by specifying the configuration file, either
+  using command line option `--config foo.cfg` or encoding it into executable
+  name `foo-clang`. Clang behaves as if the options from this file were inserted
+  before the options specified in command line. This feature is primary intended
+  to facilitate cross compilation. Details can be found in `docs/UserManual.rst`.
+
 - ...
 
 Windows Support