Using an external dll targeted for .NETFramework > 3.5

Hello,

I would like to use a dll for Speech Recognition in Unity coming from Project Oxford. The dll is here.

However, once I add it in Visual Studio, I cannot compile because the dll is using .NET 4.5 and Unity only support up to .NET 3.5.

How can I use this dll in Unity?

I am ready to write a native plugin if necessary and I am glad to share the code with the community once it is working but I would need some pointer on where to start and if it possible to accomplish.

Thanks in advance!

I am working on a game using Unity3D version 5. The game should use strict business rules already programmed in a C# .NET4.5 engine. Using Xamarin/Mono, we hope to make this usable on windows, android, others… Did you get any update for this issue ?