The change in size you see might not be of the APK but of the app that gets installed on the phone. Both are different things. Let me ex. APK size is directly dependent on the Android SDK and has nothing to do with the test device. This is because APK is generated on your PC using the SDK and it is then pushed to the device via adb. Therefore APK size can't possibly be dependent on device. Installed size is the size of the app you see in settings apps app window. It shows how much size the app takes on your phone. This factor depends on the android version of the phone the runtime (ART or Dalvik) and in some cases it may also depend on ROM. This is because apk gets unpacked when it is installed in a phone and it gets unpacked differently based on different systems. Example - ART systems ( 5. lollipop) typically have larger app install sizes than Dalviks (Kitkat or lower). So I believe it's the installed size which is changing in your case and not APK. I hope this helps. Cheers U1f44d