in place upgrade from 2.2 to 2.4?

[Carl Brewer]

G'day,
I'm running Cyrus imapd on NetBSD (pkgsrc), my current version is 
2.2.13, and I figure it's about time to bump it to 2.4 (.7 ATM).   Via 
pkgsrc I can build it, but am a bit reluctant to do a make update, does 
anyone have any experience with doing this in place on a current site? 
Will it 'just work' if I shut down the 2.2 processes, update cyrus and 
restart the daemons or will weird things happen?  any doco on how to do 
this?

Thanks!

Carl