I ran the update from 5.0.11 with no major issues (some corrupted tables that I had to repair for zimbra logger). The install finished, but hung at starting services. After waiting for quite awhile, I rebooted.
Everything appeared to come up properly, but the server is not working. Here are the oddities I have found so far:
zmcontrol status yields "Unable to determine enabled services from ldap. Enabled services read from cache. Service list may be inaccurate." and reports everything running.
ps aux | grep amavisd yields quite a few "amavisd (virgin child)" I don't believe this is how things should be.
I've done a chown zimbra:zimbra and a fixperms already, but we still aren't up and running.