The .NET Framework 4 is a Microsoft runtime environment that requires apps for Windows, Windows Store, Windows Phone, Windows Server, and Microsoft Azure. The Microsoft Office in particular is dependent on the .NET Framework. This makes the Microsoft .NET Framework something similar to the Java Runtime Environment (JRE), which requires Java programs as a runtime environment.
.NET in different versions
The .NET Framework was released by Microsoft in version 1.0 in January 2002 and has since been released in several major versions. These do not necessarily contain the previous versions, so that version 3.5 must be installed in addition to version 4.x if Windows software names the Microsoft .NET Framework 3.5 as a system requirement.
For the subversions of Microsoft .NET Framework 4 this looks different, for example version 4.7 replaces its predecessors as an update. However, there are differences in the system requirements. While version 4.0 still supports Windows XP and Windows Vista, version 4.7 only starts with Windows 7.
If you still need the .NET Framework 2.0, 3.0 or 3.5, you usually have to install the Microsoft .NET Framework 3.5 and the Microsoft .NET Framework 3.5 Service Pack 1 (SP1), because versions 2.0 and 3.0 are included.
Programming for .NET
The .NET Framework provides a runtime environment for Windows apps when the C#, Visual Basic, or F# programming languages are used during development. The system provides language and framework enhancements for writing source code. Included are various concepts to enforce security policies for programs such as authentication, authorization, isolated storage, and encryption. A fast reacting user interface as well as a supplement of ASP.NET or Windows Communication Foundation (WCF) complete the system.
.NET is Open Source
The .NET Foundation was established in 2014 when Microsoft placed the .NET system under an open source license. The foundation takes care of the open source projects around the Microsoft .NET Development Framework and provides a forum for the community and commercial developers. Besides Microsoft Windows the .NET Framework for Linux, Mac OS X and FreeBSD should be available. Until then, Mono is still available for Linux as a freeware alternative.
Install .NET Framework 4
NET Framework 4 runs under the Windows versions Windows 10, Windows 8, Windows 8.1, Windows 7, Windows Vista, Windows XP, Windows Server 2003 SP2, Windows Server 2008 R2 SP1, Windows Server 2012, Windows Server 2012 R2 and Windows Server 2016. However, it depends on the subversion. While version 4.0 is available for Windows XP to Windows 7 and the corresponding server versions, version 4.7 is available for Windows 7 to Windows 10 and the corresponding server versions.
As a download itself, Microsoft only offers the online installer via the download button, which downloads the necessary files during the installation via the Internet, so you must have a fast Internet connection. Alternatively, there are standalone variants that contain all files and can be installed offline. They are primarily available for the Windows Server and can be downloaded under “Additional Information” if they are offered, which varies depending on the subversion.
In particular from Windows 7 and under Windows 10 the installation can be carried out online via the operating system. Under Windows 7 you have to click on “Activate or deactivate Windows functions” in the system settings under “Programs” and activate the checkbox before Microsoft .NET Framework 4.7 in the next window. The situation is similar under Windows 10, where the path “Settings > Apps > Programs and Features” leads to the Control Panel and the link “Activate or deactivate Windows functions”. The checkbox before Microsoft .NET Framework 4.7 must also be activated in the window that opens. After a click on “OK” the software will be installed via Internet.