Apple is releasing two software updates today for its mobile devices and wearables, namely iOS 12.4.1 and watchOS 5.3.1. These are small-ish downloads (101MB on iOS, 55MB for the Apple Watch) that provide important security and stability updates, and are recommended for all users, according to Apple’s spartan changelogs.
The two updates should have already hit your respective iDevice or Apple Watch, in case they haven’t just hop into Settings (on iOS) > General > Software updates, or go to the Apple Watch app > My Watch > General > Software Update for your wearable.
Although Apple is staying mum on the issue officially, rumor has it the iOS update is actually released in order to re-patch a jailbreaking vulnerability that somehow made its way back into iOS with the 12.4 release, despite having initially been suppressed in iOS 12.3 and subsequent versions.
Apple iOS WatchOS Firmware Updates