But would IRC be what a post-Discord exodus actually goes back to? Lacking basic modern amenities like seamless scrollback and push notifications is going to be a hard sell for the generation that grew up with Discord. As a sibling mentioned, Matrix is closer to the mark.

Doesn't matter. IRC serves a niche that there's always a community for that no matter how small it'd become. I'd place a bet that it won't die as long as there's computer and internet. Long live IRC.

> seamless scrollback and push notifications

Both are doable with modern servers and clients thanks to v3 chathistory. Ergo (server) and Goguma (mobile client) in particular make this work very nicely.

There is also Zulip, that I think is opensource.

Can vouch for Zulip. Threaded messaging is the best.-

v3 has a lot of features folks don’t talk about. But XMPP MUCs are still kicking too.