September 12, 2018
You can now submit apps that take advantage of the powerful new capabilities in the next release of iOS, watchOS, and tvOS. Build your apps using Xcode 10 GM seed, test with the latest releases of iOS 12, watchOS 5, and tvOS 12, and submit them for review.
Starting March 2019, all new apps and app updates for iPhone, including universal apps, will need to be built with the iOS 12 SDK and support iPhone XS Max. All new apps and app updates for Apple Watch will need to be built with the watchOS 5 SDK and support Apple Watch Series 4.