When running build with Xcode 12.0.x error occurs:
[Transporter Error Output]: ERROR ITMS-90534: "Invalid Toolchain. Your app was built with an unsupported SDK or version of Xcode. If you plan to submit this build to the App Store, make sure you are using the versions listed in https://help.apple.com/xcode/mac/current/#/devf16aefe3b or later."
It seem Xcode 12.0.x needs to be updated.