转自：https://blog.csdn.net/h_o_w_e/article/details/79874162
根据Android 7.0的兼容性文档（https://source.android.com/compatibility/7.0/android-7.0-cdd.pdf）
里面7.3.4 Bluetooth部分描述：
Android Watch implementations MUST support Bluetooth. Android Television implementations
MUST support Bluetooth and Bluetooth LE. Android Automotive implementations MUST
support Bluetooth and SHOULD support Bluetooth LE.
Device implementations that support android.hardware.vr.high_performance feature MUST support
Bluetooth 4.2 and Bluetooth LE Data Length Extension.
Android includes support for Bluetooth and Bluetooth Low Energy . Device implementations that
include support for Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features
(android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and implement the
platform APIs. Device implementations SHOULD implement relevant Bluetooth profiles such as A2DP,
AVCP, OBEX, etc. as appropriate for the device.
可见官方文档在Android 7.0才要求支持蓝牙4.2