Xcode8 B4 can't upload ipa for TestFlight test?

I'm seeing this issue as well with B4

ERROR ITMS-90534: "Invalid Toolchain. New apps and app updates must be built with the public (GM) versions of Xcode 6 or later, OS X, and iOS SDK or later. Don't submit apps built with beta software including beta OS X builds."

Filed rdar://27663268

Per the TestFlight release notes, not supported yet:

https://developer.apple.com/testflight/release-notes/

This has been taking about a week for each beta release.

Thanks Hunter! Hadn't seen that yet.