CKNotificationInfo's desiredKeys with CKDatabaseSubscription

Is it possible to use the CKNotificationInfo's desiredKeys property for the CKDatabaseSubscription?

I'd like to use have access to those values in the AppDelegate function...

Code Block
application:didReceiveRemoteNotification:fetchCompletionHandler:

When I try to create subscriptions with desiredKeys, I get an error reading "cannot add additionalFields to this subscription type."

Is that for real? Can we not use desiredKeys with CKDatabaseSubscriptions?
CKNotificationInfo's desiredKeys with CKDatabaseSubscription
 
 
Q