Xcode 11 and iOS 11
Please note that apps built with Xcode 11 using named colors may experience lookup failures (with no value returned) when the app runs on iOS 11 or earlier. This will be fixed in a future Xcode update. To avoid this issue, raise the minimum deployment target to iOS 12 or later to submit to the App Store now, or rebuild with the next Xcode GM candidate seed when it’s available.