JMAP for Calendars, Contacts and Files Now in Stalwart

We need better client support for JMAP. Apple Mail, Thunderbird, Outlook (as if), and so on. I'm surprised some of the smaller ones like Canary or Spark don't implement it as a product differentiator.

Serious question: what’s the differentiator if major email providers don’t support it?

(This should not be interpreted as a defense of IMAP.)

One big differentiator is JMAP allows one network connection to track new emails that may get delivered across different folders. With IMAP you need a connection open for each folder.