Firmware Version 2.0.0 incorporates the following enhancement:
Support for the “panning” scene mode with the EOS 90D has been added. The Panning scene mode reduces subject blurring and blurs the background when the lens is mounted to the EOS 90D.
This firmware update is for lenses equipped with older firmware versions. If the lens’s firmware is already version 2.0.0, update is unnecessary.
The version of the lens firmware can be checked on the camera menu.