Android P is getting a neat new Bluetooth feature
With the update, Android will start storing the last volume used on each device in a preference file and will be to automatically apply the correct volume setting the next time you connect that particular device. This feature has been a part of iOS for some time and is sure to be appreciated by Android users who stream audio to Bluetooth devices on the regular.
Speaking of volume settings, Android P will also shift from the current horizontal volume slider, to a vertical one with a mute button below. This one is more of a cosmetic change, though the vertical orientation does seem more intuitive, seeing as how volume rockers are always on the side.
source: XDA
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