I've heard that using Slack with biboumi as a gateway is better than their gateway ever was, but can't say myself. I'd be curious to get your experience if you try it.

Does that help if they're also turning off the XMPP gateway?

I thought biboumi also supported Slack natively, but I might have been mixing it up with one of the others. Spectrum maybe? "I've always heard that using a third party gateway which uses the Slack API to communicate with slack is a better experience" is probably what I should have said.

No. What SamWhited probably meant is “It’s better to use XMPP-client -> biboumi -> slack’s irc gateway -> slack than XMPP-client -> slack’s XMPP gateway -> slack”. Because otherwise, the comment makes no sense, since biboumi is not a native Slack gateway.

So, since both XMPP and IRC gateway will disappear, it does not help.