@mahoneyt944 Sorry, my explanation was not completely correct: It's the firmware that is updated, as far as I can see the PCB itself looks identical. But you can find out which firmware runs on your PCB, simply by pressing both mouse buttons simultaneously and keeping them pressed for 10 seconds. If this switches the mouse axis from horizontal to vertical, your PCB is running the latest firmware. Otherwise it still runs the old firmware.
Apparently there is no simple way to update the firmware yourself, they simply sent me a new PCB.