AIR Not Ready for iPhone X?

So I'm just now submitting my first app update for iPhone X. I added the Default-375w-812h@3x.png image and it looks and works great on my iPhone X. But when I submit to the App Store, I get an error when I include a screenshot for the 5.8-inch display.

The app previews and screenshots for the iPhone 5.8-Inch display won’t appear on the App Store because your binary wasn’t built with the iOS 11 SDK.

I am using AIR SDK 27.0.0.128 and my guess is that it doesn't indicate something quite right in the metadata for the .ipa file.

FWIW, the submission still seemed to work. It is just a warning. But I assume that iPhone X users won't see the screenshot specially made for the iPhone X.