Nikon announces a new firmware update for the mirrorless Z 7 and Z 6 full-frame cameras. It upgrades the products with eye-detection autofocus (AF) for still-image shooting. The update also enhances the cameras' low-light AF detection range, and adds an auto-exposure tracking capability to their 'burst' modes.
https://www.notebookcheck.net/Nikon-s-new-software-update-for-the-Z7-and-Z6-models-adds-eye-detection-autofocus.420824.0.html