iOS option is disabled in Version or platform (iTunes Connect)
I had the same issue. I had to reject an app that was in "Waiting for Review" status since we had to update a bug that we found after we submitted the previous build. Once we did that, we were unable to add a new version and the ios option was disabled. To fix this:
I went to the same version that showed "Rejected by Developer",
Scrolled down to the build version,
Clicked the minus (-) icon next to the previous build to remove that,
Added the new build and
Saved and Submitted for review.
The version increment automatically updated after step 5 above based on the selected build.
I found the solution. In my case I wanted to update the app to a newer version which wasn't listed in the "+Version or Platform" menu. The possible reason is that a previous build failed, with the status of "Prepare for Submission".
- Select the build which is listed as "Prepare for submission" under "iOS App".
- Scroll down till you see the build for that submission.
- Delete the old build and select a new correct build.
- Now scroll down more and change the version of your submission in the textfield to the build number of your correct build.
After doing that I was able to submit it to the App Store.