With the announcement in Microsoft’s build 2015. Microsoft stated Windows 10 will be significantly easier to port Android and iOS app to Windows. Not only that but Windows 10 will also contain a built-in emulator. With that transition will the Networking class in Unity finally be accessible in Windows store apps? Or maybe in the near future?
Current networking classes will never be supported.
Unity 5.1 will include new multiplayer networking APIs (codenamed UNET) that will work on all windows platforms.
Great news! If and when you need beta testers, sign me up. 
There is this thread for 5.1 - Unity Engine - Unity Discussions , but 5.1 beta is available only for Pro customers