You need the Microsoft .NET Framework 4 SDK (part of the Windows SDK for Windows 7 and .NET Framework 4).
. You can develop for an older environment (like a server running .NET 4.0) while using a newer version of Visual Studio (like VS 2019 or 2022). Microsoft Learn Legacy Support microsoft .net framework 4 multi targeting pack
it whispered in a calm, robotic voice. "I contain no runtime. I am a ghost of the past, dressed in the clothes of the old framework." You need the Microsoft