Dear Sebastian,
A typical model of distributing the release version of a mobile app is via an app store (Google Play Market for Android).
If you use it for your mobile app and post new versions of the app to the app store, users who installed the app from the app store will be notified that a new version of the app is available and will be able to update the app.
If you install a preliminary version of your mobile app to a limited number of mobile devices, you can automatically update the XML configuration of the app on the mobile devices via the web server to which you publish the XML configuration.
Best regards,
Vladimir Gurov