https://www.theverge.com/circuitbreaker/2018/4/18/17251412/android-p-bluetooth-headphone-volume-settings-update

Android P is finally fixing its Bluetooth volume settings with an update that will allow the mobile OS to remember volume preferences on a device-by-device basis, according to Android Police.

Now, Android will store the last volume used on each device in a preference file and automatically set back to that the next time you connect to that device. It’s not exactly a big change, but as someone who regularly switches between blasting music through a Bluetooth speaker and listening to music on a pair of headphones, it’ll be nice to not have my eardrums blown out every time I switch between the two devices. (And yes, iOS has been able to do this for a while, but it's nice to see that Android is catching up to help protect my hearing.)