The title says it all: what CLR version is / will be needed to run C# 6 programs? The CLR version is interesting to find out the system requirements and supported operating
C # 6 language enhancements is compatible to .net framework starting from 2.0 to 4.6. It does not require any higher version of .net framework but need higher version of Visual studio such as VS 2015. C# 6 is also available to VS 2013 with addon https://github.com/dotnet/roslyn