Any modern android phone (cheapie will do) - as long as it has a minimum version of android 4.0 (Ice Cream Sandwich), though we would recommend at least Android 6. Note that the old device's Bluetooth app is for emergency functionality ONLY, i.e. you cannot reset service reminders or bleed brakes, etc with this app, this app is to get you out of a pickle in the middle of nowhere (a GS calling 911), when you don't have a laptop nearby.
A diagnostic tool for BMW motorcycles. View live data and fault codes etc.
play.google.com
Also, the market places are flooded with clones, should yours have come with a CD, read up on counterfeit devices:
www.hexgs911.com
Kind regards and safe travels