JMAP is a new protocol that is introduced by FastMail as a proposed replacement for IMAP (and friends) for an open standard solution to doing push updates to email.
While I completely agree with them, this is needed, currently there’s no universal solution, etc etc. However it ticks the same box as most “we could stop spam dead” solutions…. everyone would have to adopt it.
Not only that, but it’d have to be added to all the existing (boring, unfun) infrastructure code (like postfix, exchange, etc) to provide the services to all the mobile providers.
Will have to see if it goes anywhere.