There are still a LOT of IRC users. Though I mostely use it for development channels. #Unity3D on freenode for example has 223 users active. #go-nuts even has 1273 users.
I personally like it much better then Discord as it's just simpler and cleaner.

I don't know if this is just me being one 'a dem youngins, but haven't most people passed from IRC to Discord by now?

Hi there everyone,

Since im rather looking forward to playing Due Process, I've made an IRC channel to chat about it. Please do drop by and have a chat about the game, its game design and other related topics.

Irc adress: #dueprocess @ irc.gamesurge.net

IRC Webclient: https://kiwiirc.com/client/irc.gamesurge.net/dueprocess

P.s. For those new on IRC. It is a rather slow chat channel, so the chances are high people won't respond and will answer after a while.

Unofficial IRC Channel