I’m using this app to check the targetAPI of the apps, but at Nov 2018 every app update (and new app) has to have at least targetAPI 26 -> see also Important TargetSDK and NDK changes in Android app publishing.
And you should understand the differences between targetSDK and minSDK. My minSDK is 19 (Android 4.4), so I’m sure the C++ code can’t use newer features. My targetSDK is 27 (Android 8.1), so I’m sure, the Java code is checked against it by lint while compile time.
Any other questions?