Which Unity Version to Program KSP Mods?

[PalowPower]

Title says everything

[ValiZockt]

You don't need any Unity version to programm KSP Mods. You just need an IDE where you can write your code and compile it. (I personally use Visual Studio 2019 Community Edition, but you can use any IDE that suits your needs).

If you really need to do stuff in Unity (which is rare), use Unity 2019.2.2f1

See this thread for more information.