diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 8f5ca9b3c2d..aca2ebb8e8a 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -8,6 +8,9 @@
 ;; Keywords: comm, processes
 ;; Package: tramp
 
+;; This is a GNU ELPA :core package.  Avoid functionality that is not
+;; compatible with the version of Emacs recorded in trampver.el.
+
 ;; This file is part of GNU Emacs.
 
 ;; GNU Emacs is free software: you can redistribute it and/or modify