https://arstechnica.com/gadgets/2019/05/apple-releases-ios-12-3-macos-10-14-5-watchos-5-2-1-and-tvos-12-3/

Today, Apple began rolling out new versions of its iOS, macOS, watchOS, and tvOS operating systems for iPhones and iPads, Macs, Apple Watches, and Apple TVs, respectively.

The updates are largely focused on the video services that Apple announced at its March 25 event—namely, a revamped Apple TV app, Apple TV Channels, and an expansion of AirPlay 2 to devices produced by Apple's partners. A handful of bug fixes, performance optimizations, and other small tweaks are also included in the updates.