In the 5.2 and 5.3 releases we've migrated our local data layer from the file system to a database fronted by the Yap Database project. However, in supporting our widget and notifications we believe that Yap Database will not be a sustainable interface, particularly for multi-threading cases. To provide a more stable long term data layer we will transition to the CoreData data persistence interface provided by iOS and remove our use of Yap Db.
For the end user there should be no difference in behavior of the app. Therefore the acceptance criteria will be our standard regression suite, particularly cases related to updating app versions and saving pages.