Hi SwellJoe,

Mattermost team here. We've had requests for XMPP, and potentially it can be added in future. Feature idea can be tracked here (and more ideas welcome!): http://mattermost.uservoice.com/forums/306457-general/sugges...

That said, communication has changed significantly since the XMPP standard. For example, after we implemented markdown in Mattermost it's really hard to go back (http://www.mattermost.org/open-source-slack-alternative-adop...).

If you decide to try Mattermost, please let us know if we can help! Twitter at @mattermosthq or via community options at http://www.mattermost.org/