Why does Xcode list "8 capabilities unavailable" (including Game Center) when I want to add capabilities to my app? I am registered in the Apple developer program.

Same problem here

I might be off the mark, but I think they removed this from XCode and now you enable it in iTunes Connect - go to 'My Apps', select the app (assuming you created it in iTunes Connect and then select 'features' - here you'll be able to add the GC capabilites, IAP, etc. It's what I ended up doing anyway because I had exactly the same problem - the documentation didn't match what XCode actually did.

HTH

Contacted developer support, they don't know of this problem. It's being forwared to the engineers. Marking this forum post with it.

This is what worked for me

In xCode Select Target and then General Tab (next to capabilities tab). Select the right "Team", also make sure in build settings you have selected correct provisioning profile and capabilities should appear in capabilities tab. Hope this solves the problem for you.

I've been having similar problems. Seeing "8 capabilities unavailable" in the capabilities tab for ios. Checked my keyChains, developer Certificates and IDs and provisioning profiles every which way (including iCloud container configuration). Nothing seems to work.

I have also seen commentary regarding a dependecy between iCloud and GameCenter (also a missing as one of the 8 capabilities) and some issues with GameCenter. The release notes have this entry

Certain capabilities, such as Game Center and In-App Purchase, cannot be enabled in the Capabilities pane of the Project Navigator.Enable and then disable the iCloud capability to restore the ability to enable the other capabilities. (22964531)

But it is pretty cryptic as to the fix. Anyway I have filed a bug report to see what happens.

Apple Developer Relations04-Feb-2016 07:49 AM Engineering has determined that your bug report is a duplicate of another issue and will be closed. The open or closed status of the original bug report your issue was duplicated to appears in the yellow "Duplicate of XXXXXXXX" section of the bug reporter user interface. This section appears near the top of the right column's bug detail view just under the bug number, title, state, product and rank. If you have any questions or concerns, please update your report directly here: http://bugreport.apple.com/.

Wow. All I had to do was go to the General tab, then back to Capabilities, and it worked fine. Thanks!

I can not add new feature in the itunes connect's 'features' view...

how to address this problem

Yes, same for me. For some reason I had duplicate (free) accounts, but I was the only developer here.