Key for an array containing the old and new stores.
- iOS 3.0+
- macOS 10.4+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
- Core Data
The object at index
0 is the old store instance, and the object at index
1 the new. When migration happens, the array contains a third object (at index
2) that is an array containing the new objectIDs for all the migrated objects.