Firmware Version 1.5.0 incorporates the following enhancements:
Support has been added for the following lenses: – RF600mm F11 IS STM – RF800mm F11 IS STM – EXTENDER RF1.4× – EXTENDER RF2×
Firmware Version 1.5.0 is for cameras with firmware up to Version 1.4.0 If the camera's firmware is already Version 1.5.0, it is not necessary to update the firmware.
Q&A Section: Preparations for the firmware update:
In the folder you downloaded are the firmware (EOSRP0150.FIR / file size: 34,353,808 bytes) and instructions on the firmware update procedures (a PDF file in five languages: Japanese, English, French, Spanish, and Simplified Chinese). Before starting the firmware update operations, please be sure to check the procedure in accordance with the instruction.
Firmware link:
https://www.canon.com.au/cameras/eos-rp/support?option=drivers