Once we made a new release of Android BOINC several years ago, and immediately after received several similar bug reports of the missing GPU detection. That was a very interesting case, because between the releases we made no changes to the GPU detection, and still on the same Android OS, old version was working fine, and the new one not.
Since there was no any Project that has an application for any Android GPU, this issue was classified as non-blocker, and we didn't rollback that release.
Still this case was very interesting, and I have started the investigation of it. And at that moment I started to realize, that every new Android release breaks something that was working for years. Of course, main explanation of such an actions was a security issues.
From the very beginning, Android was a very open platform (in comparison to the iOS for example), and it allowed you to do almost anything you want. But, of course, this leads to security issues, including the major ones.
Android BOINC application is very different from the Desktop implementation. First of all, BOINC Manager is written on Java and Kotlin (originally it was written on Java, but we have started to migrate it to Kotlin as it is more modern, safer and easier to maintain). But BOINC client is still written on C++, because reimplement all the functionality of it on Java/Kotlin would be too much work, and not everything required by the BOINC client was yet available (and some stuff still not) in the Android API.
But Android API from version to version started to deprecate and even remove the functionality that is crucial for running BOINC on Android. For example, we are not able to upgrade to the latest version of the Android API because then we will not be able neither to run the client natively, nor to run the downloaded Projects' applications. We spent quite a lot of time trying to understand how to proceed with this, and at that moment decided that we will stick to the current version of Android API as long as possible. But as a drawback, we are not able to publish Android BOINC on the Play Store, because Play Store policies demand to use the newer version of the Android API that doesn't work for us. That is why currently Android BOINC is published on the official BOINC website and on F-Droid (3rd party service not supported by us) only.
Another issue was with the GPUs. In this case there was a change in the API that prevented BOINC from listing available GPUs on the device. Luckily, there still was a way to implement this GPU discovery in a little bit weird way, but at least it works.
However, there is still no any Project that has the application for Android GPU, but we really hope that with the fix we provided, once we will see such a Project that will allow BOINC to utilize Android device more effectively than now.