Any plans to move up to newer versions of .Net/C#?  Doing:

Log(string.Format(".Net Runtime Version = {0}", typeof(string).Assembly.ImageRuntimeVersion));

I get the following from the log:

2013-10-12 00:00:00 .Net Runtime Version = v4.0.30319

Which presumably means the c# compiler version is 4.0.  see:

I'd like to take advantage of some C# notation like:

public Dictionary<(string, DateTime), MyClass> ...

to take advantage of composite keys in a dictionary.  Yes, I can work around this, I just need to be careful of reflexively taking advantage of newer c# syntax.  Not a blocking issue, just curious if there's plans to update .Net/c# anytime in the near future.