Firmware Version 1.1.0 incorporates the following fixes and enhancements:

1. The option to capture full HD movies and 4K UHD movies in 23.98p frame rate has been added.
2. The communication speed has been improved when connected via wired LAN.
3. The “Browser Remote” function has been added.
4. The function to transfer only protected images has been added.
5. Corrects the phenomenon in which, when the electronic level is set to “Show” in the viewfinder display, in rare cases, the camera may freeze when operating the AF-ON button or shutter button.
6. Corrects the phenomenon in which the Custom Shooting Mode settings may change when the shooting mode is switched.

Firmware Version 1.1.0 is for cameras with firmware up to Version 1.0.0. If the camera's firmware is already Version 1.1.0, it is not necessary to update the firmware.                   

1. After the EOS-1D X Mark III is updated to Version 1.1.0 (or later), it cannot be restored to a previous firmware version (Version 1.1.0 to 1.0.0).
2. Camera setting files created with EOS-1D X Mark III cameras running Firmware Version 1.0.0 can be uploaded to EOS-1DX Mark III cameras running Firmware Version 1.1.0.
3. Camera setting files created with EOS-1D X Mark III cameras running Firmware Version 1.1.0 cannot be uploaded to EOS-1D X Mark III cameras running Firmware Version 1.0.0.

About Browser Remote:

4. When using Safari with iOS 13 or iPadOS 13, multiple images can not be downloaded.
5. When using Safari with iOS 13or iPadOS 13, the logged-in state will expire after a while and you will be asked if you want to continue with the session.

Notes:

Please download the most recent version of the User Guide.

Download Firmware Version 1.1.0 for the EOS-1D X Mark III.

If you have not already done so, please register the EOS-1D X Mark III. By registering, we will be able to notify you via email about future announcements.

Thank you, Customer Support Operations
Canon U.S.A., Inc

Email: carecenter@cits.canon.com
Support options and hours of operation: www.usa.canon.com/support