Updating apps is handled differently depending on how the app was installed:
Pushed through Mobile Manager, either Free or Paid. – iOS
We are looking into the possibility of supporting this at a later date after intensive testing.
Uploaded App or Enterprise App – Android, Windows, and iOS
To update this type of app, an admin user must upload a newer version of the app to the same group that the app is located at. Uploading the app to a child group will not cause the app to update; the upload will just fail.
Learn more about Uploaded Apps here.