Cyrus may offer the best implementation of cards and calendars ( https://en.m.wikipedia.org/wiki/Comparison_of_CalDAV_and_CardDAV_implementations ) but would you trade its imap for dovecots own? 

I am starving for an open-source card and calendar solution that is sound and secure, so cyrus is a good candidate, but I need it to go along with the existing structure, i do not want to start fresh with a new imap server. 

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Am 30.06.2018 um 07:13 schrieb Mihai Badici: > I can confirm you can use dovecot ( instead of cyrus) but is not trivial > and I didn't know much about the compatibility for shared calendars. Cyrus IMAPd provides exactly that, easily ;-) https://www.cyrusimap.org/imap/download/installation/manage-dav.html Alexander