I'm looking to use UWP API's with a DLL I develop with VS 2017 and I need to get access to 'Windows.Foundation.UniversalApiContract' and 'Windows.Foundation.FoundationContract' winmd files. I found this manual page and switch my project to UW platform with latests windows 10 sdk (10.0.07763.0). I've set the Scripting Backend to IL2CPP, Scripting Runtime Version to Experimental (.NET 4.6) and API Compatibility Level to .NET 4.6. I'm using latest Unity 2017.4.27f1. But directive #if ENABLE_WINMD_SUPPORT seems actually false, even with configuration done above. I can't access to Windows API from my C# scripts like UnityEngine.Windows.Application.InvokeOnUIThread() Any hint on what could be wrong and how could I enable Windows Runtime support ?