I finally found an S9 Duos for a reasonable price with a little damage on the display, so I could find out why my app fails. A fixed installer app is available in the forum.
Recently my Play Store phone book app offered to download a plugin which re-enables access to the call logs. While this worked for the paid version, the trial version was immediately blocked by Google due to a "policy violation".
After thinking long about how to handle this situation I came to the following conclusions:
All app versions will be free from now on!
So you can all move to the fully functional version without having to pay again. I'm sorry for all the problems recently - it was not my choice.
Recently more and more Samsung phones are released with the dual SIM option in all markets and they don't support rSAP out of the box. So I though I should try to find out why my app also does not work on these phones. I bought a cheap Galaxy J3, checked what happens inside my app and got it running!
So if you have a S9, S10, A6 or whatever recent Samsung Duos phone (and it's already rooted) you may test my app with this installer version in the forum.
Currently I'm a bit confused. I am pretty sure that a few weeks ago I had a warning in my Play Store developer account page that I should remove the READ_CALL_LOGS permission. The last mail I received stated that apps which still use this permission on March, 9th will be delisted.
Now it's the 13th, the app is still listed and the warning in my developer page is gone. Has Google withdrawn the new policy?
Update: meanwhile the apps were blocked. Since it looked like Play Store will also stop the licensing for a blocked app I'll try to find a solution for the Play Store versions.
Recently Google changed some conditions for publishing apps in the Play Store which make it necessary to leave:
This means that background processing is hard to acomplish. Both apps implement a Bluetooth profile which should be ready at all times, so it must run in the backgrounnd. With API 26 this is only possible by showing a notification icon (currently optional for rSAP). And you still have to manually except the app from power save functions. If your app tries to automatically remove itself from this list it is immediately banned from Play Store.
This affects the phone book app. It's pretty useless without the possibility to transfer call lists to the car. Of course I tried to get an exception for the phone book app by filling out some "Permissions Declaration Form", but I got as answer:
The declared feature (Connected device companion apps) is allowed; however we determined it to be unnecessary for the core functionality of your app.
I don't understand how Google determines that call logs are "unnecessary for the core functionality" of the phone book app, maybe it is some Google AI :-( I guess Google simply rejects all requests.
So I decided to move my phone book app to Amazon Appstore. It is basically the free trial version with the possibility to unlock full functionality with in-app payment.
If you already bought the phone book app in Google Play Store it is also unlocked. Update: this only works for me as the developer, sadly not for users :(
In a few weeks the paid version will be unpublished by Google and I will publish a trial version which informs the user about the full version being available in Amazon App Store.
As soon as the rSAP app needs an update it will also move to Amazon...