From my understanding, .NET Fx 1.x and .NET Fx 2.0 will likely "always" be supported on Windows. Both Fx 3.x and Fx 4.x have no trouble "pretending" to be 2.0 i

From my understanding, .NET Fx 1.x and .NET Fx 2.0 will likely "always" be supported on Windows. Both Fx 3.x and Fx 4.x have no trouble "pretending" to be 2.0 in a backwards compatible way and 1.x is small enough that Windows just still bundles it in about the same way that Windows still bundles the VB6 runtime. If you want the most "ultra-portable" executable for .NET Framework, you could choose 1.1 or 2.0. Picking 1.1 in 2023 is about as silly as picking VB6, it also won't feel just about anything like modern .NET. 2.0 feels a lot more like modern .NET (especially because that's when Generics and Generic Collections first exist), but also not really something I'd recommend in 2023. (But in theory targeting .NET Fx 2.0 gets you ultra-portable all the way back to Windows 98.)