Noticed several days that some IETF people are apparently working on IMAP4rev2. Even further, the work was started back in 2015 and is still active.
Sadly, it is just merging extensions. [imap5] mailing list is still quiet as a graveyard, you know.
A general furry public instance. You don't have to be a furry to join. Any and all topics are fair game provided they do not conflict with the Code of Conduct.