Read original post at Sebastien Pertus' Blog
Since the Windows 8.1 launch, we can use a new feature, called Brokered Component, to manage legacy components and then writing code for Modern UI application that call desktop .NET objects (pretty cool !).
You can create a Brokered Component project within Visual Studio 2013. You need to install new templates projects, available here : http://visualstudiogallery.msdn.microsoft.com/527286e4-b06a-4234-adde-d313c9c3c23e