Our app is in most cases compatible with all available Android phones and tablets. Because we started really early we have app versions for Android starting with version 2.3, so a really old phones that aren’t sold today anymore. In some cases Play shows that our app is not compatible with a device. The most common reason is that you bought a device without GPS module. Because we are vehicle tracker GPS module is a must, so before purchasing a device make sure it has GPS.
Google Play can also show you why the app is not compatible, it’s well described in this article http://lifehacker.com/google-play-shows-you-why-an-app-is-incompatible-with-y-496328577