title: iPhone:Updating a Core Data Model in Future Versions of an App
body: <p>I am releasing a Core Data based app and wondered what I need to consider if, in an update later down the line, I need to change the model.</p>
  
  <p>How do I move existing user data on the device from the old data model into a new updated model?</p>
  
  <p>Thanks</p>