The Scirra build service only supports Android 5.0+, which covers about 85% of devices worldwide (and still increasing). Supporting Android 4.x is possible with Crosswalk, but this will significantly increase the size of the APK. Also Crosswalk has been deprecated by its developers so is no longer supported, and to build with it you'd need to do a manual build with the Cordova CLI. I think only supporting Android 5.0+ is a reasonable compromise.