Why do you need to migrate?
When you release an app and add new features, there will be a time you need to update you persistent store. This is easy to do when you are in a development stage, because you can just delete your app and the persistent store will be re-generated. But when you are live and people have downloaded your app, you need to be careful. They won’t like it if suddenly their saved data has disappeared!
Continue reading How to do a lightweight Core Data migration