Chat over IMAP seem a bit misleading title. Their proposition is to add additional info in MIME headers. Or later some of them like Message-Id with chat info. So seem more related to MIME and SMTP. A client app can get those headers with different protocols too. MAPI, EWS, JMAP, etc.

We are working on server specs, the idea is that certain functionality like WebPush, WebRTC calls, channels require the servers to support COI.

Do you know, is it going to have a demo/beta server just to play it.

Chat over SMTP/IMAP/MIME just doesn't sound right, or does it? We also thought of Chat over Email, or Chat over Mail, But Chat over IMAP gave us the COI (fish), which we love. Decision made :)

Chat over Email is so much clearer as a name.