Yeah, our clients are on Framework I feel your pain.

...But reading between the lines, you probably still have clients on XP (.NET 4.0). That's gotta sting. We made a fuss about TLS1.2 support being required and forced them to upgrade to Win7/.NET 4.5.2 at least.

I have gotten gotten a smallish winforms app to work with the new .csproj format. But it's painful. WPF is probably a nightmare.

As an aside if you make it to .NET 4.5+ and get async/await. It works great with winforms and presumably WPF!