Debian Sarge, Kopete with KDE3: 256M of RAM, AMD Athlon 2000.

Windows 11, Discord: 4GB are not enough to run it well.

FYI, Kopete allowed inline LaTeX, Youtube videos (low res, ok, 480p maybe, but it worked), emoticos, animations, videoconference, themes, maybe basic HTML tags and whatnot. And it ran fast.