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
Apple Releases macOS Mojave 10.14.6 Supplemental Update 2
The macOS Mojave 10.14.6 Supplemental Update can be downloaded by going to the "Software Update" section of System Preferences and selecting the Update Now option. There are also updates available for macOS Sierra and macOS High Sierra.
There's little detail on what's included in today's update, but Apple's release notes say that it "improves the security of macOS" and is recommended for all users. According to a support document, it addresses a vulnerability that could allow remote attacker to "cause unexpected application termination or arbitrary code execution."
The next-generation version of macOS, macOS Catalina, is still in beta testing and is set to see a public release sometime in October, though Apple has not specified when.