Vehicle autofocus tracking; improved masked face detection; smoother low-light EVF performance; better helmeted and behatted face/head detection; and several networking workflow improvements are on the way. At least for users of the Canon EOS R5 and R6. “Flagship” owners of the 1DX Mark III will get just a few of these features, but can enjoy all of them if they are to “downgrade” to the definitely-isn’t-a-flagship EOS R3 to be launched in the same end-of-November timeframe.
The new firmware boost is expected to drop right around the time of the R3 launch. Canon commonly waits until a new camera is released with new features prior to bringing them to earlier legacy cameras.