Currently, five core versions of the Microsoft .NET Framework have been released:
The final versions of the 1.0 SDK and Runtime were made publicly available in January 2002.
Microsoft . NET Framework 1.1 was released in April 2003, and was mainly bug fixes for 1.0.
Microsoft .NET Framework 2.0 was released in November 2005 and contains: 64-Bit Platform Support, Access Control List Support, new features in ADO.NET, significant enhancements to all areas of ASP.NET, Authenticated Streams, COM Interoperability Services Enhancements, and more. Please see the Microsoft Web site for further information. Service Pack 1 for the Microsoft .NET Framework 2.0 was released in November 2007.
Microsoft .NET Framework 3.0 was released in late 2006 - early 2007 and is installed with Microsoft Windows Vista. Service Pack 1 for the Microsoft .NET Framework 3.0 was released in November 2007.