diff --git a/lisp/gnus/pgg-def.el b/lisp/gnus/pgg-def.el
index b8d9cbec807..046f57dbbfe 100644
--- a/lisp/gnus/pgg-def.el
+++ b/lisp/gnus/pgg-def.el
@@ -29,7 +29,8 @@
 
 (defgroup pgg ()
   "Glue for the various PGP implementations."
-  :group 'mime)
+  :group 'mime
+  :version "21.4")
 
 (defcustom pgg-default-scheme 'gpg
   "Default PGP scheme."