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 Seeds Mac OS X 10.5.3 9D34 to Developers
Once complete, the final Mac OS X 10.5.3 update will become available as a free update to existing Mac OS X 10.5 (Leopard) users via Software Update. No target date is set, but testing has been ongoing for two months and Apple's Worldwide Developer Conference (WWDC) is just around the corner (June 9th).