Had to dig through a lot of forum posts to finally find this. There’s a notice on top of the docs at Chat & Chatbots | Twitch Developers suggesting that it will be discontinued, so people were saying twitch is killing the irc interface with no replacement at all in the new api, which seemed too stupid to be true.
You really should update that misleading notice, it’s creating FUD out of nothing, and as far as I can see this post in this forum is the only thing stating otherwise.