You can only add WinMD references to a project targeting Windows 8.0 or higher. To learn how to retarget your project to ...

You can only add WinMD references to a project targeting Windows 8.0 or higher. To learn how to retarget your project to a different version of Windows, please see the 'Core subgroup' section underneath the 'Windows tab' section in the 'How to: add or remove references by using the Reference Manager' help page: http://msdn.microsoft.com/library/hh708954(v=vs.110).aspx.