.NET 1.0 (13 Feb 2002)
This was the first version of .NET and it contained first common language runtime along with first set of framework class libraries. It was introduced with the first version of Microsoft visual studio.
.NET 1.1 (24 Apr 2003)
This was the second version of .NET framework. It contained updated ASP.NET and ADO.NET features. It also had the capability to run one application on single machine with multiple CLR versions. It has two service packs i-e SP1 and SP2 which further improve the performance of the framework. It was released with Visual Studio 2003.
.NET 2.0 (7 Nov 2005)
The third version brought significant improvements with the advent of new CLR. It also improved several framework class libraries and added new libraries as well. This version also contained two service packs. It was released with Visual Studio 2005.
.NET 3.0 (6 Nov 2006)
.NET 3.0 contained all the capabilities of 2.0 with the addition of Windows Presentation framework, Windows Workflow Foundation and Windows Communication Foundation known as WPF, WF and WCF respectively. This version also had couple of service packs. It was released with Visual Studio 2005.
.NET 3.5 (19 Nov 2007)
LINQ and Ajax were the two major features which were added in this version of the product. Dynamic data controls were added in the first update of the product. It was released with Visual Studio 2008.
.NET 4.0 (12 April 2010)
This was another major release by Microsoft as it brought the CLR 4.0 in the market. Other important features of this version include Managed Extensibility Framework (MEF), code contracts and Dynamic Language Runtime. It was released with Visual Studio 2010.
.NET 4.5 (15 Aug 2012)
This is currently the latest version of .NET Framework it has an updated CLR with improvements to ASP.NET, ADO.NET, WPF, WCF and other framework class libraries. It also supports windows app building. It was released with Visual Studio 2012.
This is currently a preview version of the .NET framework with improved performance and debugging capability. It has improved windows store app support. It has been released with Visual Studio 2013 preview.
Why use .NET Framework?
Following are some of the features which make .NET framework, best for application development.
CLR and MSIL code, also known as managed code are the best features of this product. CLR and managed code makes the .NET application portable with any Microsoft platform.
.NET framework supports multiple languages and these languages can be used in combination with each other owing to the CLR which makes programming lot more flexible.
Framework Class Libraries provide variety of built in features which promote the principal of reusability reducing the amount of code required to be written manually.
.NET framework makes the deployment of the application extremely seamless and efficient using built in deployment features.
.NET applications are lot more secure and the framework contains built in security features specifically for web application.
With .NET framework most of the memory management tasks are hidden from the developer which makes application development much more easier and fun to do.