Currently Being ModeratedDec 7, 2012 5:50 PM (in response to BobF4321)
I don't recommend updating to Server.app 2.2 yet. So leaving the old version installed for now is the best option. I just got off the phone with Apple Enterprise Support and was told of a known-issue: I could not replace a self-signed cert with a verified cert at the moment. It's completely broken for me and the rep wasn't surprised. Most of Apple's services require a cert to work properly. So, if you're using certs at all, stay away. Certs added prior to 2.2 appear to function normally.
To answer your original question: only core server functions are stored within the Server.app package including some helpful reset scripts. All of your settings should be stored in /Library/Server
Once you delete Server.app, it stops all services. Your settings will be reloaded once you run the new Server.app. I haven't seen any issues with this in 2.1.1 or 2.2 -- both on 10.8.1 or 10.8.2.
That assumes that everything was setup properly from the beginning. When in doubt, do nothing. Updating the server isn't something anyone should really be doing right now. Unless it's in a test environment.
Currently Being ModeratedDec 14, 2012 1:47 AM (in response to rmmr)
Hi rmrrm, after 2.2 update i've got some problems on Wiki and Profile Manager and i'd like to reinstall Server App but i don't wnat to lose users (open directory) and mails. You said that settings will be preserverd after Server App reinstallation. Also users and mails?