What do I have to do to get Core Data to automatically migrate models?

Question

I have read the documentation about automatic /lightweight migration for Core Data models - but I am having problems implementing it.

As I understand it the applicat

Answer 1

Minor edit to @Grouchal's awesome instructions above for Xcode version 5:

Old: 2. Select the Design Menu at the top - then Data Model - then choose Add Model Version

Version 5+: 2. Select the Editor menu, then Add Model Version…, type your Version name and Based on model (select your original model from the list)