Got this answer from Apple Support today:
Hello,
Thank you for contacting App Store Developer Support regarding not able to add a new version of your app in iTunes Connect.
Thank you for reporting the issue you are experiencing. We are aware of the issue. Our teams are actively working to resolve this as soon as possible. Your patience is appreciated during this time.
If you would like to provide any feedback regarding this or anything else, you can reply to this email and I would be happy to forward it to the appropriate team for review.
Don't hesitate to contact us if you require assistance with any other questions. You can fill out a Contact Us form in iTunes Connect here:
http://www.apple.com/itunes/go/itunesconnect/contactus
If you have any questions or concerns, you can reply to this email or contact us via phone, Monday-Friday, 9:00AM-7:00PM central time at 1-800-633-2152 or
Worldwide Developer Support Phone Numbers
http://developer.apple.com/contact/phone.html
Please reference your follow-up number: 1155450633
Best regards,
Bobbie
Apple Inc.