Error submitting to itunes connect -- assets catalog

I’m currently getting the following error trying to upload to itunes connect.

ERROR ITMS-90596: "Invalid Bundle. The asset catalog can’t be read. Try rebuilding the app with a non-beta version of Xcode and submit it again.

It seems to be an issue with a not updated Xcode and/or OS X. http://stackoverflow.com/questions/39461567/xcode-8-gm-seed-error-while-uploading-to-testflight

It looks like circleCI still uses 10.11.6. Anyone know a way to use an updated version?

Thanks