Recently I deployed the ZXtras suite and tested a few of it's functions. I have disabled all features aside from chat. Chat worked well and is fairly easy to manage.
Shortly after this I installed the zMantis zimlet. This zimlet allows integration with Mantis Bug Tracker. You have to execute a few command line options that enable JSP and add a proxy domain for the Mantis server.
So all of this appears to work in my account. Chat runs, I see users. zMantis works. I can send bugs to our Mantis Bug Tracker.
In other accounts, lots of stuff is broken. The main showstopper is the fact that some people can no longer click on folders within Zimbra. The folder doesn't open anything and you notice, with each click, the details for "Folder", "Size" and "Received" all start to crunch over leaving no blank spaces between the fields.
Aside from this, zXtras chat stops working for the same accounts that experience the issue above. Other accounts, seem to be fine.
Note, recently we have performed the migration below. Everything went very smoothly and appears to operate 99%(weird mobile email responses have stripped formatting)
ZCS 7.1.3 (CentOS 5 64-bit) --migrate new box--> 7.2.7 (CentOS 6 64-bit) --upgrade on same box--> 8.5.0