Before updating an application using the AIR 2 or earlier Application Updater framework to the AIR 2.5 namespace, update to the AIR 2.5 Application Updater framework. Attempting to update directly to an application using the AIR 2.5 namespace fails.
Make two updates to the application. First update only the Application Updater framework to the AIR 2.5 version. Then update the application descriptor file and the application.
The example below shows the recommended steps for updating an application to the 2.5 namespace. The example assumes that the current version of the application is installed is 1.0. It also assumes that you are updating to version 2.0 that uses the new features in AIR 2.5. Finally, it assumes that all update-related files (update descriptors, new applications) are stored at http://www.example.com/updates/. (Change the path to suit the particular configuration of the application you are updating.)