Please note: the original post mentioned the EOS R6 Mark II, that was obviously nonsense…
Canon released a new Canon EOS-1D X Mark III firmware. It’s version 1.6.2.
Canon EOS-1D X Mark III Firmware Update Version 1.6.2 incorporates the following fixes:
1. Fixes an issue that, in rare cases, displays an Error Code 70 after the camera has been connected to a network for a prolonged period of time.
2. Fixes minor issues.
If the camera’s firmware is already Version 1.6.2, it is not necessary to update the firmware.