My company recently upgraded their XMPP server for internal chat, and now require the Jitsi client. I don't know if Jitsi is nice on Windows, but the Mac version is like having bleach dripped in my eyes. After Apple's Messages app, Jitsi is a travesty.
Messages connects fine, does everything Jitsi does, but gets disconnected with a "this is an unapproved client" message.
My XMPP admin, a hacker at heart, wondered out loud whether there is a way to make Messages report to the server that it IS Jitsi. I've learned that this is usually a hint at what I should google to get around various IT roadblocks, but in this case he may really have been just idly wondering.
XMPP is all XML. Surely "the client I am" is just a field in the message document. Anybody have any idea how I could spoof my client name?