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 2022-10-31, Dovecot doesn't support JMAP yet). However, a new JMAP server in Rust has emerged: https://stalw.art/jmap/

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