This is factory firmware version 56.04 for Axpert King 3kW Rack Mounted models with the '28066 processor. The nominal voltage is 48 V despite the "3.24" in the original rar file name. dsp.hex file is dated 7/Oct/2021.
Do not use with any other model, and only if the existing firmware is 56.xx. Note that there are several other models with 56.xx firmware, do not confuse them.
Use at your own risk.