I tried to upgrade my UCS test VM to version 5 and it failed to upgrade properly. I only had mail server and the two self service apps installed.
I’m not sure what all the problems were, but I think this will keep me from upgrading any UCS servers for the time being as I think all of the ones that I help administer have one or both of those options installed. Some have more apps, but this is a pretty minimal example.
I have reverted my VM to the last snapshot and I will test again after the next update to see if things work any better.