Android Question Anyone using Google's In-App Update function?

For the last couple of days, I have been testing Google's In-App Update function by using ArminKh1993's library https://www.b4x.com/android/forum/threads/in-app-update-library.126305/#content. It was working really well, with my test app detecting a new version being present on the Play Store almost immediately after the new version had been uploaded. (This is using the Internal Testing track.) However, this morning I uploaded a new version and the test app started returning 0 as the value for availableVersionCode. Since then, I have not been able to get the test app to report any other number, including reverting to a previous working version (with an increased version number). This is a similar behaviour to that reported here https://www.b4x.com/android/forum/t...ry-returns-version-0-b4xpages.129649/#content and here https://www.b4x.com/android/forum/threads/alternative-to-inappupdate-library.134722/#content.
The functionality provided by In-App Update is really useful, so I was wondering if anyone is successfully using In-App Update, either via ArminKh1993's library or some other route?
Thanks.