I’m syncing with CloudKit encrypted databases and had issues after upgrading to DTTG4. I reported them on another thread.
The issue was that although my databases were «present» displaying all items, I could not download any on IOS. I found that the syncstore had disappeared from my sync settings. When I re-created it, there was strange behaviors, the sync store was duplicated and it took much time to synchronize. But finally it worked. I did it slowly, database by database and device by device (iphone and ipad).
They told me that there was a bug in version 4.01 and that 4.02 was on the trail.
As soon as it was published on the App Store, I updated. It still works well but the duplicated sync store is still present. I didn’d see an option to remove it, just to «clean», which I did on my iphone, with the store that was uncheked. Result was a complete re-sync with the other checked store.
Maybe another update will help remove the unecessary sync store.