iPhone 6 -- 8.2 BT 3.0

I Downloaded a app called Bluetooth spy. when opening app it says it doesn't support BT 3.0--my headset is 3.0. Does this mean it is communicating at 2.0 or 2.1.

how can I see what the connection is at? On like a pc you can see what the link is at but I can not find where to check on iPads or iPhones. Thx