Apple released numerous software updates on July 22 for the Mac, iPhone, iPad, iPods, Apple Watch, Apple TV, and HomePod along with updates to some older iPhones and iPads.
This includes iOS 12.4, macOS 10.14.6, watchOS 5.3, Home Pod, tvOS 12.4, and security updates for some older iPads and iPhones. This could be the last release prior to iOS 13 and macOS 10.15 Catalina.
Before proceeding backup your devices.
Learn more at https://9to5mac.com/2019/07/22/ios-12-4-release/