Old Android version (4.4 on my side) didn’t look for shared library by SONAME inside. It only checks file name. For example, in recent Android version (7 or 8), one file named libcrypto.so whose SONAME is libcrypto.so.1.0.0 can be loaded by dependents successfully. But in old versions the system reported “dlopen failed to load libcrypto.so.1.0.0”.
In Linux’s programming conventions, a shared library usually has name like libxxxx.so.x.y.z and a symbolic link named libxxxx.so would also be created pointing to the former. That’s OK in a normal Linux system, but has problems with Android’s app. The android apk’s zip format didn’t recognize symbolic link, and as I described in 1. it also didn’t load shared library by SONAME.
Android Studio integrated CMake to build native libraries and it also packs what generated by CMake (app/build/intemediates/cmake/<debug-or-release>/obj/<arch>)/) to libs directory inside the apk. That’s good. But! But it packs only files with .so extension. So, files like libxxxx.so.x.y.z would be packed into the apk, and we don’t have any configurable option on both gradle file and CMakefile.txt to add them manually.