Brilliant stuff, but kind of sad that this hasn't caught on already. I realize that standardization has only firmed up recently, but other standards like HTTP and TLS see preview releases supported in major products well before they are finalized.<p>Who uses JMAP besides FastMail?
> JMAP is therefore not introducing any new measures to address end-to-end encryption.<p>It seems like a wasted opportunity to not make E2EE a primary focus of a new email standard. Hopefully there will be standard extensions down the road to add this if JMAP takes off.
IMO, as a user the biggest advantage is mail being sent via the same protocol as it is received. Someone made an IMAP extension to do that but unfortunately it was never widely implemented.<p>Some aspects of JMAP haven't made it through the standards process yet, like calendars, quotas, and server-side S/MIME signature verification. Hopefully it will get wider implementation from the big email companies once those are complete.
How do various mail clients talk to their respective backends? I.e. what does iOS Mail use to talk to iCloud? The GMail iOS app speaks a bespoke binary protocol to Google's servers, not IMAP.