This is a removable display firmware update file for Axpert MAX models: 7.2/8/3.6/4 kW, 48V or 24V. NOTE: NOT for MAX II models with the fixed display with round LED effects. The mcu.hex fils is dated 2022/Aug/16. Use at your own risk. Must be updated via a Windows PC, compatible USB to serial cable, and original RJ-45 to RS-232 (D9) cable. Firmware update instructions here.