iPhone application prob after updating the app

I have one application named A with version 1.0.

I have updated it with different features and database changes. The database and features are totally different from the older version.

Now, some of users are unable to run the application after updating the new version. They need to reInstall the new v开发者_StackOverflow社区ersion.

Its not happening with all. Please suggest.

If the database is based on Core Data and you've changed the data model, this changes the database schema, and so you'll need to set up a migration path for the user's documents to be migrated from the old to the new version. Read Apple's Core Data Model Versioning and Data Migration Programming Guide.