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

I was having the same issue with Xcode 8.3 public version. I reinstall the Xcode and check it, but didn't work ...

Finally I found the issue , I have mistakenly selected Xcode 3.2-compatible in project format under project document. I changed it to Xcode 8.0-compatible and build & archived it. I could upload it without any errors. Check the screen shot attached ..