. It does not use a traditional "license key" or serial number; instead, license file that is tied to your specific PC Bluetooth Battery Monitor How to Get a License
The software is open-source. Modifying or reverse-engineering it to bypass a non-existent key is unnecessary. If a specific developer releases a paid version, attempting to bypass payment constitutes software piracy. alternative a2dp driver license key
If you truly cannot afford the $8, use the "separate microphone" trick or the Linux dual-boot suggestion. If you can afford the headphones, you can afford the driver that makes them work. alternative a2dp driver license key