The evolution history of C# is as follows:

C# 1.0

1. Managed Code

2. IDE - Visual Studio 2002, 2003

3. .NET Framework - 1.0, 1.1

C# 2.0

1. Generics

2. Static Classes

3. Partial types

4. Anonymous methods

5. Iterators

6. Nullable types

7. Asymmetric Property and Indexer Accessors

8. Delegate Inference

9. Covariance and Contra-variance

10. IDE - Visual Studio 2005

11. .NET Framework - 2.0

C# 3.0

1. Implicit types (var)

2. Partial Methods

3. Object and collection initializers

4. Auto-Implemented properties

5. Anonymous types

6. Extension methods

7. LINQ

8. Query expressions

9. Lambda expressions

10. Expression trees

11. IDE - Visual Studio 2008

12. .NET Framework - 3.5

C# 4.0

1. Dynamic binding

2. Named arguments

3. Optional Parameters

4. Generic Covariance and Contra-variance

5. COM Interop

6. IDE - Visual Studio 2010

7. .NET Framework - 4.0

C# 5.0

1. Asynchronous methods

2. Caller info attributes

3. IDE - Visual Studio 2012, 2013

4. .NET Framework - 4.5, 4.5.1