Canon EOS-1DX Instruction Manual page 360

3 Saving and Loading Camera Settings
Loading Camera Settings
In step 2, select [Load from card]. Up to ten camera settings files
saved in the card will be displayed. When you select the desired file, it
will be loaded and the settings will be applied to the camera.
Compatibility of camera settings file
A file saved by a camera having firmware version 2.x.x cannot be read
by a camera having firmware version 1.x.x. A file saved by a camera
having firmware version 1.x.x can be read by a camera having firmware
version 2.x.x.
Up to ten camera settings files can be saved in a card. If the card already
has ten camera settings files, you can either overwrite an existing file,
replace the card, or save to another card.
Camera settings files saved with a camera other than the EOS-1D X
cannot be loaded to this camera.
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