Older versions of Kanda Software will not work with latest FTDI USB driver 2.12.36, released 17/06/2021. This applies to PIC and AVR handheld programmers, AVR keyfob and AVRISP-U programmers.
The solution is to roll back the driver to 2.12.28, released 16/08/2017.
Kanda have released a free Android App, for smart phones and tablets, that lets you update your AVR or PIC handheld programmer contents from your phone. Just load the programmer, copy it to a programmer file (.PRG), send it to your customer, distributor or engineer and they use their phone or tablet to update the programmer.
Atmel have added a new feature to Atmel Studio from 6.2 on-wards including 7. You can now create a single file that contains all the data needed to program an AVR or ATxmega microcontroller. This includes flash, EEPROM, fuses, lock bits and ATxmega User Row. This is called an ELF production file and Kanda AVR Handheld Programmers now support this format.