I know this question had been asked in different versions already many times, but none of the answers helped me. I developped an app, that works fine on my mobile phone, but often can not be installed on the phones of my friends. I checked the device features my app needs, but they don't seem very unusual. the android minSdkVersion is also ok, and the apk has a normal size

I can not reproduce this problem on the emulator. even one of my apps, which is not compatible with my tablet on Google play, works perfectly when I run it locally while developing. so how do I find out, what device feature, or what other problem is preventing my app from being installed? 

Here is the link to one of my apps on google play that causes this problem: [serial call](https://play.google.com/store/apps/details?id=at.richardlederer.serialcall)