thanks for your response. I might give up for now until there's a better solution. Although I can't imagine that it's so complicated, because there should be so many apps out there that need to support collaboration...haven't got CKSubscription to work yet. Also I was thinking that when I add the CKShare Record to the Core Data private database, then it will be synced and part of core data database, which should complicate things as it might lead to doubled records? Or am I thinking the wrong way here? Please let me know if you find a solution and if yes, what the solution looks like. I'll let you know as well.Thanks!Katharina