I started feeling bad about having used mIRC for 20ish years without paying for it so I switched to HexChat. It does everything I need and has a simpler interface, but I do sometimes miss the hacked up pirated copies of mIRC that were customized with scripts to do different things.

>Edit: Hm, seems it was some time ago I checked out the news/blog of HexChat, seems like last version was a year ago.

Pretty sure it's had security updates more recent than that, but I don't really pay attention.