watchOS apps for the App Store must be built with the watchOS 2 SDK starting June 1

Starting June 1, all new watchOS apps submitted to the App Store must be native apps built with the watchOS 2 SDK [software development kit] or later, according to a note on Apple’s developer website.

Apple says that with the new features and capabilities that watchOS 2 brings to WatchKit, apps can integrate even more closely with Apple Watch. The company encourages developers to take advantage of the Digital Crown, microphone, Taptic engine, and health sensors to take your Apple Watch app to the next level. And with ClockKit, apps can be extended to the clock face with Complications.