For those who still like the classic style of messengers, Psi [1] offers an old-school, extremely customisable interface, and is still actively maintained. It integrates nicely with all the desktop platforms as well.
Kinda. The normal version hasn’t seen a release in 4 years, only the experimental psi+ version is maintained, and it is unclear which features it actually supports as all (at least in the wiki in English) information is heavily outdated.
I agree, that takes me back. I miss a lot of old things. Some things haven't changed though, I still use irssi in XTerm!