Please see: blogpost16-WikiSuite-will-now-support-all-major-Linux-distros. While ClearOS's mail stack is powered by Cyrus IMAP, Virtualmin's mail stack is with Dovecot, so we will focus on efforts there (As of 2021-10-14, Dovecot doesn't support JMAP yet).
WikiSuite will add support for JMAP via a combination of contributions to Cyrus, Cypht integrated in Tiki Wiki CMS Groupware and the IETF standardization process. Please see: Cyrus IMAP 3 and JMAP development
- Cyrus IMAP 3 and JMAP development
- Next generation SIEVE standard: https://datatracker.ietf.org/wg/extra/about/
- Here is an example: https://ietf.topicbox.com/