Aspects of IRC that IRCv3 (supposedly) is not addressing/did not address:
Does not provide an easy way to upload a file in-band to a public channel (you can't share code snippets, photos, or videos with your irc client, you need to use a web browser) https://github.com/ircv3/ircv3-specifications/pull/341 ←– might be able to also include file uploads, WIP
Does not sync messages properly on phones (messages are often lost or repeated) Elaboration needed as to what exactly is meant; IRC session on phone A is 100% independent of IRC session on device B. Bouncer relaying? if that, then statement is true
Does not provide recipient confirmations for when a message is delivered (echo-message only provides server confirmations, not recipient confirmations) https://github.com/ircv3/ircv3-specifications/pull/346 ←– WIP
Does not provide buddy lists MONITOR (similiar to WATCH) as possibility?
Does not provide HTTP tunneling to bypass firewalls Outside of their scope likely, networking issues created by ISP's, which IRCv3 does not work with in an official capacity
Cannot handle frequent disconnects from mobile clients Has to do with mobile connections frequently “dialing into” the next available “post”/source and apple shuts down background processes of non-apple apps after 3 minutes; beyond the scope of IRCv3 and perhaps not fixable at all
Cannot handle audio/video calls https://github.com/ircv3/ircv3-specifications/pull/341 ←– could be used with Jitsi Meet
Does not provide a standardized registration interface https://github.com/ircv3/ircv3-specifications/pull/276 ←– resubmitted and still considered non-deployable; grounds for IRCNow to work and improve (requires client authors to integrate a good GUI though)