We’ll be updating the email stack during the Virtualmin 8 dev cycle. It’s tricky to make changes to the email stack, as it’s so complicated, and active users will have custom procmail rules and such, and procmail goes away in any mail stack overhaul (replaced by Sieve). It’s plausible we’ll switch off of Dovecot, as well, as Cyrus supports JMAP, while Dovecot doesn’t, and it might be nice to have that for an overhaul of Usermin.
Anyway, it’s very likely we’ll have a new mail stack in time for Virtualmin 9 in early 2027, and folks can probably try it as we develop it, though I wouldn’t recommend a switch on production systems until it’s stable. Again, very complicated, lots of moving parts and dependencies.