This is a blessing in disguise. There is nothing you need for the ST16 in Play Store, so there is no reason to ever go there with your ST16. Never loose sight of the fact that this is you flight controller, not your personal android device. That is what your other smartphones and tablets are for, ...remember they don't control your aircraft!
Another fact that is often overlooked, if you have ever looked over the list of "Privileges" Play Store requires, you will see it demands nothing short of Administrator privileges over your entire device. This is NOT something you want lurking in the background of your controller while you are flying! Unlike other devices, this one is dedicated to one app and one task: Flight Control. Let it do its job unmolested by other apps.