[QUOTE=JulmaHerra;1483535]I don't, but I do have suspicions that either implementation is bad, non-standard or CalDAV/CardDAV standard per se is not very good if some implementations work and others don't.

I think the problem lies in not entirely the CalDAV part but Jolla's sync framework and local storage of event data.

For example, the hour difference problem is quite possibly because of timezone differences. eg. I'm in the UK which is an hour out from central Europe CET. My server is running CET. Apple's servers are probably US West coast time. Phone is GMT/BST.

If you add an event on my Mac, it goes to the server and the time is correct. It syncs to the Jolla and is 1 hour out. Correct it on the Jolla and it doesn't sync to the server. On next sync, it dissapears from the Jolla.

Dates and times in the CalDAV standard are stored in either local time, UTC or local time with timezone info.

I would guess the Jolla is doing a full sync when I start a new account to test and so pulls in the event. It then gets the event but screws up the time when storing it locally. On the second sync the same event UID now matches two different events so the server throws an error back to the Jolla to deal with it and the Jolla discards the event rather than mess up the server which should always be treated as the "truth".

Yep. I would guess the conflict resolution in ActiveSync is based on the server rather than in CalDAV where it throws an HTTP 409 error and expects the client to deal with it. Or perhaps the ActiveSync code on the Jolla is just more mature.

Buteo Sync dates back to Nokia and seems to have been written by someone as a summer placement. The only part that worked then was syncing with Google.

Z-Push is still using proprietary protocols, open source or not. Microsoft require licences for some parts of the protocol which is patented. This used to be client licences so device manufacturers paid for the licence but changed to be server based. This is why Google started shifting away from using ActiveSync and Microsoft had to rapidly implement CalDAV/CardDAV support in Windows Phone or otherwise loose gmail users.

That would be because Lotus Notes has chosen to licence and implement only some of the features in the full Exchange Active Sync protocol as has Z-Push. Neither are full implementations.

Then again, Lotus.