Can't submit apps to AppStore: ERROR ITMS-90534: "Invalid Toolchain

Question

ERROR ITMS-90534: \"Invalid Toolchain.

New apps and app updates must be built with the public (GM) versions of Xcode 6 or later, macOS,

Answer 1

Right-Click on the archive file (.xcarchive) > Show Package Contents > Products > Applications > Right-Click on the app file > Show Package Contents > Double-Click on Info.plist to edit it

Remove b from the end of the value for DTXcodeBuild (for example change from 9C40b to 9C40)

Re-submit and it will work