We saw the most renowned features included in recent versions of the C# language and .NET Framework from their 4.0 versions.

We covered the C# 4.0 version, with a review of Delegate and Interface generic variance (covariance and contravariance), dynamic declarations, argument improvements, tuples and Lazy Instantiation of objects, which implied important changes in expressiveness and the power of the C# language.

Then, we gave a brief introduction to the async/await structure as a means to simplify asynchronous calls by coding the two parts usually required in only one method.

Next, we did a review of the most important features included in version C# 6.0, which is mainly based on new ways to reduce verbosity in the language.

Finally, we've seen the most important features added to the recently published version 7.0, which are mainly based on syntactic sugar to make expressions more meaningful and the new pattern matching features which make the use of tuples a very feasible option in many common situations.

In the next chapter, we'll do a comparison of languages, including the F# and TypeScript support in Visual Studio as well as provide some prospects about their use in the future.