Apple on Tuesday released watchOS 4.3.1, a minor update to the Apple Watch operating system. The minor update brings mostly bug fixes and other behind-the-scenes performance enhancements.
In addition, as of watchOS 4.3.1, developers are no longer allowed to update apps built on the watchOS 1 SDK, which debuted alongside the original Apple Watch. Starting with watchOS 4.3.1, users will see a warning when launching an original watchOS 1 SDK app, telling them that the app may not be compatible with future versions of watchOS.
The warning strongly suggests support for watchOS 1 apps will be dropped entirely in the near future, perhaps as early as next week, when watchOS 5 debuts at the Worldwide Developers Conference.
The update also includes a fix for a bug that could cause the Apple Watch to occasionally stick at the Apple Logo during startup on some devices.
Apple Watch users can download the new update via the Watch app on their iPhone. Go to: “General” -> “Software Update.” Before attempting the update, make sure your Apple Watch has at least 50% battery power remaining, is placed on a charger, and is in range of the connected iPhone.