https://developer.apple.com/ios/submit/
Build with iOS 11 SDK
Update your version of Xcode to the latest release of Xcode 9 available on the Mac App Store, which includes the iOS 11 SDK, and build your apps. Starting April 2018, all new iOS apps submitted to the App Store must be built with the iOS 11 SDK. All new apps for iPhone, including universal apps, must support the Super Retina display of iPhone X.
"must support the Super Retina display of iPhone X." must be support iPhone X layout?