As you've discovered, the original creation date isn't a property of the iCalendar object itself. There is a sequence number that's incremented on every revision, which might help in tracking down the info you need.
If the appointment is a meeting you could try to find the meeting request in someone's sent mail or trashcan, but that's not guaranteed.
If you have all your mailbox.logs, you can search through them. For example grep <accountname>.*CreateCalendarItem mailbox.log will turn up any appointments created via ZWC that occurred during that mailbox.log. Different patterns will search for appointments created by CalDAV or ZCO--you just need to experiment. (Or you can search by keyword in the name of the appointment.)
Note: the mailbox.logs (located in /opt/zimbra/log) are rotated nightly, and get deleted after 10 days. But you could probably find a way to increase the retention period, or (perhaps better) simply back them up. |