[the_common_man]

There is also cloudron.io. It has imap/smtp/sieve/catch-all/relaying/aliases/tagging/rest api. Fairly complete. https://cloudron.io/documentation/email/

[nullwarp]

My only complaint with cloudron is that the auto-update mechanism requires a subscription. You can manually upgrade, but it's awkward and I broke it more than once while trying.

[type0]

Can you use one subscription to update multiple cloudron VPS servers or would you need to have a separate for each one?