Well, it does not ask for a reboot but to change the version number you will need to do it manually or, what is the most common thing, see it on next reboot.

About the clean notes into the message body, can you try ‘Settings’ on my signature?
UseAlternateRtfSyncing value under [MailScanner] section.
See screenshot of settings here: http://forum.avast.com/index.php?board=2;action=display;threadid=9514