Zimbra Migration: Calendar ICS Import/Export
The Zimbra Webmail Client can Import and Export calendar data in ICS format. Here is how:
Download ICS - Login to your previous calendar provider or calendar application and export the data in ICS format. Reference the Help pages for the application or service provider to learn how to export your calendar data.
Upload ICS - Login to https://zimbra.xmission.com and navigate to the Preferences tab. In the upper left portion of the screen will be another sub-menu for Preferences. Click on Import/Export. Under the Import header click on the Choose File button. Select your .ICS file and hit Import.
This begins your calendar file upload. Most imports are quite quick.
Press Save before exiting Preferences tab. Restarting your webmail session is advisable.
More information about calendars:
Video tutorials on Zimbra Calendar are available here: http://help.zimbra.com/videos/8x/
Calendar overview: http://help.zimbra.com/videos/8x/Calendar_Overview.mp4