They don't use the word "experimental" any more but they call it a "work in progress": https://www.cyrusimap.org/imap/developer/jmap.html https://www.cyrusimap.

They don't use the word "experimental" any more but they call it a "work in progress": https://www.cyrusimap.org/imap/developer/jmap.html https://www.cyrusimap.org/imap/developer/jmap.html bottom of the page.