Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
macOS Catalina Now Available
Fixed Apple TV 6.0 Update Reinstated After Being Pulled for Bricking Issues
Following the software’s initial Friday release, there were multiple reports that the update caused critical errors for a number of users, necessitating a full iTunes restore. The newly updated software presumably fixes those issues.
The Apple TV's 6.0 software offers a number of new features, including iTunes Radio, iTunes Music Store purchases, iCloud Photo updates, Podcasts, and AirPlay from iCloud. It can be downloaded from via the Update Software tool in the Apple TV settings menu.