Use .NET 4.5 on the game project

Is there a way to change the .NET version of the game project to .NET 4.5?

As far as I know it is .net 4.5 but the portable subset version of it. Your windows project should use the full .net 4.5 version. Using portable subset is to maintain cross platform support.

But I need to use Lidgren for networking, and that doesn’t work. All the stuff from System.Net is missing.

If your game is Windows only, that’s definitely something you could do. However, this is a manual process (Visual Studio doesn’t provide this tool, and neither does Paradox Studio).

Note that medium term, we will likely move from PCL to .NET Core, which features a much substantial subset of the .NET Framework.

Yes my game is Windows only. What is the process for doing this?

I got it working! I just created a new C# class library, and edited the game project until it was a normal class library too by comparing them.

That was the way I was going to recommend you, great you could do it by yourself!