As of August 1, 2021, the Google Play Store imposed a new technical requirement on all apps: to be 64-bit format rather than the old 32-bit format. The vast majority of Android devices support 64-bit apps, but very old devices (pre-2017) may not -- many of those support only 32-bit apps.
To comply with the Google Play Store requirement, we upgraded WolfQuest for Android to 64-bit format. Therefore, those very old   32-bit devices cannot run this new version of the Android game. We are looking into ways to support both 32-bit and 64-bit devices, but technical complications may prevent this. 
Again, this change is due to a new Google Play Store requirement that we must comply with. We apologize to players with old devices that cannot run the updated game. If you have such a device, please bear in mind that if you buy a newer Android device, and use the same Google account as  before, the game will run on your newer device and your purchases will be restored.
Here is more about the topic for those interested: