The firmware update for the cross-type sensors at the outer areas of the frame is still not released (for Nikon D5, D850 and D500)



Time seems to stand still at Nikon. When the Nikkor 180-400mm f/4E TC 1.4 FL ED VR lens was announced, Nikon promised (in the press release) to release a firmware update for the D5, D850 and D500 that will make the outer row of AF points activated as cross-type sensors to significantly enhance the AF coverage throughout the frame. Nikon USA says on their website that the new firmware is expected in March 2018 (click for a larger view):



As of today, unless I am missing something, the firmware update is not yet released.

Additional information on Nikon’s 153 AF focus points can be found here.

Nikon D850 camera autofocus (AF) coverage