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.)

Fastmail supports it, and it sounds like Thundermail will too