In 2013, I purchased the MK2/4 controller and software for it.
The controller was purchased as a spare part and did not participate in the operation of the equipment, that is, it has a new condition.
In the failure of the previous controller, I tried to use MK2 / 4, but the CNC USB Conrroller software offers "Please upgrade firmware to version 20141103" and then "Firmware update FAILED! (Unknownl)".

The controller did not work all this time and the possibility of its failure is minimal.
Controller number 04377, purchased 2013-03-04 invoice 96/2013,
Software purchased May 23, 2013 via PayPal Transaction ID: 2J964592FN896863R

The key was received by your letter from 2013-05-25, the controller was successfully verified.
Is it possible to solve this problem or the controller just failed?