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

An error message it self says, Use stable (not beta) version of Xcode to create a build. Your mac OS should also be stable (not beta)

Use latest stable version of Xcode Tool (Xcode 9) to create your build and upload using Application Uploader.

Ensure following points, while creating your build:

• Xcode version (Latest stable version of Xcode Tool - Current Xcode 9)
• Mac OS version (Latest stable MacOS version - High Sierra 10.12.7)
• Xcode Project (Document) Format version (Xcode 8.0-compatible)