jabber: 20170106.1603 from MELPA
emacs: GNU Emacs 25.3.1
OS: FreeBSD x220 11.1-RELEASE amd64
I can signin to Slack's XMPP gateway using Jabber, but only individual users appear in the Roster, not any channels (which I imagine would be MUCs in Jabber).
Further, I can't choose any extant Slack channels when executing jabber-muc-join.
I think this is related to: https://emacs.stackexchange.com/questions/13899/connecting-to-slack-channels-with-jabber
I have raised a support ticket with Slack, and directed them at this bug. I'll post any updates here.
It looks like the Slack folks are well aware that their XMPP gateway isn't standards compliant.
I've re-opened the issue, and asked them whether they have any intention of fixing the problem.
They're defintiely not going to be fixing it :(