Hi,If that is what you need, then you should checkout SOGo, it works with the components you've described below, and adds ActiveSync to the mix. (and CardDAV / CalDAV).
You could then decide to drop squirrelmail, or simply continue using that as well for email.
MJ Op 30-5-2020 om 21:14 schreef Gokan Atmaca:
Hello I am using Postfix. (Postfix, OpenLdap, Dovecot, Squirrelmail) My goal is to synchronize contacts and calendars. I have to do ActiveSync for this. How can I resolve ActiveSync ? Is there an open source solution ? Thanks.