Adding a New Version to a managed Object Model
In the project navigator, select the managed object model.
Choose Editor > Create Model Version.
In the dialog, choose a name for the model, and if necessary choose the target for the model.
Add a new version to your managed object model when you need to change the schema in an application you have already released. To convert existing persistent stores to the new schema, use Core Data’s migration feature; see the definitive discussion for information on migration.
Core Data ignores the name of the model, so you can use your own naming scheme to keep track of revision numbers.
If you do not have a versioned model, you must first convert it to use versioning.
If you are using a source version control system such as Subversion, ensure that the new model version file is added to your repository.
© 2012 Apple Inc. All Rights Reserved. (Last updated: 2012-01-09)