I am using ZD 1.0.3 (Build 1696) on OSX. Backend is ZCS Network Edition 5 (I think 5.0.16 or 5.0.18)
I have two big issues.
The first is that appointment invitations from Thunderbird+Lightning and Google Calendar do not appear as invites. I am not offered the usual Accept/Tentative/Reject buttons. However if I log into the web interface, they are recognized and meeting invitations, and proper action is taken.
Second is the calendar in ZD seems to live out of sync with the server. I accepted an appointment in the web interface, and three hours later it is still not showing in ZD. I have quit ZD, I have even shutdown the service and let it restart by relaunching ZD, to no avail. The "in sync" indicator is green and says Status: Online in the tooltip.