I downloaded this app because the built-in functionality in my Android devices only sync my primary calendar from my work Zimbra account. I have 3 calendars that I need/want regular access to.
I had posted in the comment thread on the app's download page and saw a reply that this app doesn't support multiple calendars.
Without the ability to sync multiple zimbra calendars, the app is kind of worthless to me. I'll have to keep an eye on it for future updates!