This new firmware fixes a number of reported issues (especially around very small mouse movements) as well as incorporating some suggested code improvements. The serial debug output will now report the version number (1.3) to allow users to check the currently installed firmware.
Upgrading can be performed via the USB port without the need for a dedicated programmer (using the USB bootloader) - see the documentation for details. The required firmware file (.hex) is included below to allow upgrading without the need to first compile the software.