If you really insist, it can be hamfisted into IRC: https://www.youtube.com/watch?v=0R--_ATzE6o. (Though besides the official PoC https://github.com/asiekierka/voirc and my reimplementation https://spectra.video/w/vBd8cUmo9yYD5CtKbyjrL6, I have never seen this actually being used).

There are irc clients that work on mobile, like this one from the original author of sway: https://codeberg.org/emersion/goguma

It’s just they need a bouncer (an always online irc server you run) for things like push notifications (and chat history on servers without the chat history extension).

Bouncers (and some IRC v3 extensions on newer servers) allow you to be logged in to the same account from different devices.

I’ve also had some fun writing a bridge from discord to irc for some personal discord servers (but it uses some account impersonation hijinks that make it impractical for other to use).

in general discord has a very bad app and usability, irc regardless of client is a clear upgrade

I consciously use IRC like that: I don't have a bouncer, and connect only when I feel bored and want to see what is going in some channels (nowadays mostly just #emacs on Libera). I can only follow the conversation when I am online and there, and when I leave there is nothing to catch up to. In some sense it is like a digital third-space as oppose to a permanent dual presence that I have to share my attention with. Depending on your use-case this is not ideal, but for me it is a nice, relaxing addition to a lazy weekend evening when I have nothing better to do.

FTP is still used quite a bit. For what it’s useful for, nothing has come close to replacing it.

HTTP is also still somewhat popular.

But, seriously, that got me curious. There are many protocols from that early era that are still with us today. NTP, DNS, SMTP, IMAP, BGP, SNMP, NFS, ICMP. If you allow the 1990's as counting as "old" we can add SSH and SSL, DHCP, LDAP.

Yeah, but the major upgrades for things like telnet and ftp were adding appropriate encryption layers and improved authentication to include things like certificates. IRC shoehorned those into the connections awkwardly but it's still not often mandatory and registration is painful.

Also usenet is still very popular but mostly used for file sharing.

I'm here looking for other telenet (not telnet) oldheads, finding nobody.