Firmware version 1.0.4 for the EF 24-105mm f4L IS II USM enhances the effects of image stabilization when using the lens with the EOS 5D Mark IV at a shutter speed between 1/100 and 1/160 second.
Information about firmware Update
Firmware version 1.0.4 is for lenses with firmware version 1.0.3 or earlier and whose third digit in the serial number is “0” (xx0xxxxxxx). If the firmware is already version 1.0.4, it is not necessary to update the firmware. The lens firmware can be checked through the menu on the EOS 5D Mark IV.
You can download the firmware (for Windows or Mac OS X) at:
In the folder you download are the firmware (file name: EF012104.lfu / file size: 1,441,844 bytes), and instructions on the firmware update procedures.