You can automate calendar backups by using the following Linux command and add it to a crontab on a server or machine to run on regular intervals:
curl -X GET -u <USER>:<PASS> <CALENDAR_URL> -o <OUTFILE.ICS>
- your email address, firstname.lastname@example.org
- your email address password
- The location where you want to save the resulting .ics file.
- Can be found when you log into Zimbra. Select the calendar you want to download, and select Share Calendar. The URL will be given as a link at the bottom of the new window that opens. You want the one that mentions “ICS”.