I think all version are supported. XP, Vista, 7, 8, 8.1, 8.1u1, i tried on all these OS.
Metro Apps /Modern apps are not inventoried yet, but if you really love OCS, like i do, you can create a little plugin to get all these apps. I think VBS can do the trick.
I know that you can get all appx package with powershell command (Get-AppxPackage / Get-AppxProvisionnedPackage), time to run the script, put the result in a TXT file, then let OCS get the information ;) ;) ;)
Have a nice day