7
In the Visual Studio 2015 I see that it is possible to define the version of C#:
Source: http://www.codeproject.com/Tips/865579/How-to-change-targeted-Csharp-version-in-Visual-St
But in the Visual Studio 2013 installation of a package is required Microsoft.Net.Compilers 1.0.0 via nuget with a "help" from Resharper it is possible to enable support for version 6 of C#:
According to this answer (Will C# 6.0 Ever be supported by VS 2013?) in MSDN, the VS2013 would not support C version 6#.
It would be advisable to carry out this procedure and use C# 6.0 on projects in the VS2013?

The question doesn’t make much sense: "Would it be advisable to perform this procedure and use C# 6.0 in production in VS2013?". If you’re on VS2013, you’re not in production, obviously.
– Leonel Sanches da Silva
It was really confusing the term
produção, wanted to refer to projectsreais, grandes, etc. @Gypsy– rubStackOverflow