64 bit version issue in react-native android app by google play store
React Native will support 64 bit for android starting version 0.59
https://github.com/facebook/react-native/issues/2814#issuecomment-457688789
https://github.com/facebook/react-native/commit/f3e5cce4745c0ad9a5c697be772757a03e15edc5
All of the native code for an app is stored in the libs/ directory in the root of the apk. eg for compiled ARM or x86 code, you can find it in libs/architecture_type/lib_name.so.
An APK is essentially just a zip file so you can extract it with any zip tool.
The list of architectures (ABIs) is here. If you don't have directories for arm64-v8a or have x86 but don't have x86_64 then you are missing the 64 bit native code.
https://github.com/facebook/react-native/issues/2814
Facebook seems to be dragging their feet on supporting 64 bit builds.
You can check the intermediates in the build folder to see what abis you are supporting.
https://developer.android.com/ndk/guides/abis.html
Android takes the lowest common denominator of build abi. This is going to become an issue if Facebook doesn't address it soon.