Have them dial into the admin mailbox - and after entering the password and getting in - have them press 7 (on the partner messaging and perhaps a few others it will announce the release and version). If that doesn't work - have them look at the module label (e.g. Partner Mail VS 4.1, 5.0, etc.)
Tom Daugirdas,
President
STCG, Inc.
stcg.com