As someone who grew up on Windows + mIRC + vBulletin forums (late 90s, early 00s), mIRC will always ignite fond memories :)
For those who still use IRC, but maybe on other platforms than Windows, HexChat could be considered a spiritual successor to mIRC, but it's also open source and available on a ton of platforms. Just a happy user here, not affiliated in any way.
Edit: Hm, seems it was some time ago I checked out the news/blog of HexChat, seems like last version was a year ago. I still use it without problems, but maybe people could share any active forks if they know about them?
For those who still use IRC, but maybe on other platforms than Windows, HexChat could be considered a spiritual successor to mIRC, but it's also open source and available on a ton of platforms. Just a happy user here, not affiliated in any way.
Edit: Hm, seems it was some time ago I checked out the news/blog of HexChat, seems like last version was a year ago. I still use it without problems, but maybe people could share any active forks if they know about them?