The supplemental patch had a new FIXME to support syncing of instances of a calendar event. In simpleton, recurrences. Recurrence in Evolution has always been a nightmare and especially w.r.t individual backends its more than a nightmare. Chen had made quite good contributions for recurrence in evolution-data-server and some of the other backends. My synchronization stuff cannot be close to complete, if I don't have support for syncing the instances of a recurrence. Today, with a determined mind, was looking at the other backends for similar implementation and finally, got the code in place.
Testing is what makes us happy to see our code working. Well, it was working except for a specific scenario in which we have only (a) instance(s) without any corresponding master object. Hugh... I was tired finding out the roots of the cause and finally got to a point where I could say, "Eureka!! I found the reason". Well, thatz it for today and keep watching to know more about that "Eureka" stuff. ;-)