After a short delay following a bug, Apple has released watchOS 2 for Apple Watch. The new operating system was originally scheduled to be released alongside iOS 9, but Apple discovered a last-minute bug and decided to delay the release. You can now download and install the update by launching the Apple Watch app on iPhone and selecting general then software update.
WatchOS 2 brings many improvements, but the most notable is the ability for Apple Watch to run native apps. This will give apps access to critical sensors and hardware on the Apple Watch, such as the accelerometer and speaker. App opening times will also be greatly reduced. Other watchOS 2 improvements include several new watch faces and a new nightstand mode.