diff --git a/lisp/progmodes/vhdl-mode.el b/lisp/progmodes/vhdl-mode.el
index be98066a620..5eeac8af3b8 100644
--- a/lisp/progmodes/vhdl-mode.el
+++ b/lisp/progmodes/vhdl-mode.el
@@ -12,6 +12,9 @@
 ;; file on 18/3/2008, and the maintainer agreed that when a bug is
 ;; filed in the Emacs bug reporting system against this file, a copy
 ;; of the bug report be sent to the maintainer's email address.
+;;
+;; Reto also said in Apr 2021 that he preferred to keep the XEmacs
+;; compatibility code.
 
 (defconst vhdl-version "3.38.1"
   "VHDL Mode version number.")