I have submitted a new version of an app to Testflight and completed all of the meta-data and invited all required (external testers).
When one of the external testers attempts to launch the app from Testflight, they are receiving an old version of the app - even though the new version of the app is listed in Testflight. I know this because they are seeing a splash-screen which, in fact, is removed from the new version. In addition, their old version shows the splash-screen and immediately crashes.
I have compelted a number of steps to solve the problem, but to no avail. The tester has uninstalled Testflight and the old app, and attempted to reinstall - still the old version. I have set up a test account which I have used to launch the app from Testflight, on my own device. This works - I see the new version (and it runs). When the external uses this test Apple ID (same username/password) they still get the old version. This leads me to believe it's a device-level problem - since we are testing on different devices.
Why would an old version of an app be loaded in Testflight, despite showing the new version numbers in the listing?