Bluetooth Incompatibility Any Gurus Have Advice?

Bluetooth has made a lot of advances the last few years. It was 1.x and then 2.x for a LONG time, then 3 and 4 shot up seemingly overnight.

3.x and 4.x are still "new", and in my experience only weird things use them, like sporting / fitness trackers, electronic keys, and some high end headphones use the newer protocols.

Basic stereo bluetooth audio uses a profile named A2DP and I believe there's one or two mono profiles before that, they've been around since the beginning.