Use APKPure App
Get Inspector for android.os.Build old version APK for Android
Developer tool for quickly checking details of Android builds.
This small application/developer tool uses Java Reflection to display the values found in the class android.os.Build (including android.os.Build.VERSION). This is a good way to find specific build and version details about any android device. Because it uses reflection, it should show all values from any(even future) version of android.