[UE4.7.0 Bug] Deploying to Nexus 9: ERROR: Unknown NDK architecture 'arm64-v8a'

Try opening the application makefile, and replacing the info that is there with this: APP_ABI := armeabi armeabi-v7a arm64-v8a x86 x86_64 mips mips64

Save the file and try once more. Thanks!