On 12 February 2017 at 20:15, John C Klensin <john-ietf@xxxxxxx> wrote: > Yes. See above. But note that "JMAP replaces IMAP" requires > that it support identical functionality, be a superset of IMAP > function, or drop only the functions that no one is using or > cares about. Note that I'm talking about functionality, not > syntax I don't think this is true. If JMAP is to supplant IMAP - and I think that's a worthy goal even if its likelihood remains a matter for debate - then JMAP has to support the same model. The model of IMAP is that: * Each message resides in a single mailbox, * Each message has a set of independent flags, * Each message is immutable. (One could argue that other metadata exists, given ANNOTATE, but nobody [to a reasonable approximation] uses ANNOTATE). Gmail is an example of a case where the model of IMAP doesn't fit the underlying data model - this is a shame, as IMAP's original design took considerable effort to fit the wide, existing models of the time. JMAP, on the other hand, can cope with both gmail style labels and IMAP-style mailboxes, by stated design. So I'm confident that, while your statement seems incorrect to me, the corrected statement would be satisfied. Dave.