I threw caution to the wind and just upgraded 12 of mine from FW 3.10 to FW3.26. A couple of notes:
The Get Boot Information function returns hardware version 0207 but the Upgrade File Information returns 0702. Looks like the bytes are swapped.
The software disconnects the port after grabbing the boot information. It has to be reconnected on the ConfigInfo tab before porting the firmware.
I used the cable that came with the unit. It uses the bottom most two pins when they are facing you with the cable to the right. In my case, all the talk about switching between pins 1&2 and 7&8 didn't apply.
Against the recommendation of setting each battery address to 0000, upgrading the firmware, then resetting the address, I just changed the device address in the Upgrade operation group box and the upgrade was successful. I did sever all rs485 communications to each battery before the upgrade to kill all other asynchronous 485 communications.
There is no information in the zip file indicating how to determine the hardware version and as a result, which file version to use.
I do have a question though. Does FM v 3.26 change any algorithms of the BMS or does it just change the default parameters indicated above?