To determine your Mac's Bluetooth version:
- Click the menu.
- Select About This Mac.
- Click on the More Info... button. From OS X El Capitan onwards go to step 4.
- Click on the System Report... button.
- Select Bluetooth from the sidebar on the left, underneath Hardware.
- Scan down the list of information until you find LMP Version.
If your Mac is equipped with Bluetooth 4.0, LMP Version will say 0x6. Anything lower than that is an older version of Bluetooth.