NET Framework is one of the main components of the software platform programmed by Microsoft .NET. Within this collection of tools for developers, .NET Framework fulfills two functions at once. Firstly, the partially open-source framework offers programming interfaces, utilities and class libraries for the development of programs. Secondly, with its CLR (Common Language Runtime), it has a runtime environment at the ready, which enables software based on .NET Framework to run easily.
Since Windows Vista (2007), Microsoft has included the .NET Framework with its operating systems. The library and runtime environment are installed by default and automatically kept up to date via Windows Update. Since not all versions of the framework are backward compatible, Microsoft’s systems usually install and maintain multiple editions of .NET Framework in parallel.