C# Version History

Below you can see how C# has evolved over time:

C# Version	.NET Framework	Visual Studio	Important Features
1.0	.NET 1.0	VS 2002	Basic features: ·         Classes, ·         Structs, ·         Interface, ·         Events, ·         Properties, ·         Delegates, ·         Expressions, ·         Statements, ·         Attributes ·         Literals
1.2	.NET 1.0	VS 2003	It contained a few small enhancements to the language. Most notable is that starting with this version, the code generated in a foreach loop called Dispose on an IEnumerator when that IEnumerator implemented IDisposable.
2.0	.NET 2.0	VS 2005	·         Generics, ·         Partial Types, ·         Anonymous methods, ·         Nullable types, ·         Iterators, ·         Covariance and Contravariance. Other C# 2.0 features added capabilities to existing features: ·         Getter/setter separate accessibility ·         Method group conversions (delegates) ·         Static classes ·         Delegate inference
3.0	.NET 3.0/3.5	VS 2008	This version marked a major change in the growth of C#. Let’s take a look at some major features. ·         Auto implemented properties ·         Anonymous types ·         Query expression ·         Lambda expression (LINQ) ·         Expression Trees ·         Extension Methods ·         Implicitly typed local variables ·         Partial Methods ·         Object and collection initializers
4.0	.NET 4.0	VS 2010	This version had a difficult time living up to the ground-breaking status of version 3.0. But this version did introduce some interesting new features: ·         Dynamic Binding ·         Named/optional arguments ·         Generic covariant and contravariant ·         Embedded interop types Embedded interop types alleviated a deployment pain. Generic covariance and contravariance give you more power to use generics, but they're a bit academic and probably most appreciated by framework and library authors. The major feature was the introduction of the dynamic keyword.
5.0	.NET 4.5	VS 2012/2013	Here is the major features list: ·         Asynchronous members ·         Caller info attributes async and await are the real stars of this release.
6.0	.NET 4.6	VS 2013/2015	This release added many smaller features that made C# programming more productive. ·         Static imports ·         Exception filters ·         Property initializers ·         Expression bodied members ·         Null propagator ·         String interpolation ·         nameof operator ·         Index initializers Other new features include: ·         Await in catch/finally blocks ·         Default values for getter-only properties
7.0	.NET	VS 2017	The most recent major version is C# version 7.0. This version has some evolutionary and cool stuff   in the vein of C# 6.0, but without the compiler as a service. Here are some of the new features: ·         Out variables ·         Tuples and deconstruction ·         Pattern matching ·         Local functions ·         Expanded expression bodied members ·         Ref locals and returns Other features included: ·         Discards ·         Binary Literals ·         Digit Separators ·         Ref returns and locals ·         Throw expressions C# is being put to ever broader use. .NET Core now targets any operating system and has its eyes firmly on the cloud and on portability.

For more information you can visit : Microsoft documentation - C# version history