Apple is asking developers to begin building, testing, and submitting watchOS 6 apps for including the upcoming Apple Watch App Store. watchOS 6 is due for release on Thursday, Sept. 19.
Starting April 2020, all new watchOS apps and app updates submitted to the App Store must be built with the watchOS 6 SDK and support Apple Watch Series 4 or later. Developers can build their watchOS apps using Xcode 11 GM seed, test them on devices running the latest watchOS 6 GM seed, and submit them for review.