Microsoft started development on the .NET Framework in the late 1990s originally under the name of Next Generation Windows Services (NGWS). By late 2001 the first beta versions of .NET Framework 1.0 were released. The first version of .NET Framework was released on 13 February 2002, bringing

managed code Managed code is computer program code that requires and will execute only under the management of a Common Language Infrastructure (CLI); Virtual Execution System (VES); virtual machine, e.g. .NET, CoreFX, or .NET Framework; Common Language R ...

Windows NT 4.0 Windows NT 4.0 is a major release of the Windows NT operating system developed by Microsoft, targeting the data server and personal workstation markets. It is the direct successor to Windows NT 3.51, and was released to manufacturing on July 3 ...

, 98,

2000 2000 was designated as the International Year for the Culture of Peace and the World Mathematics, Mathematical Year. Popular culture holds the year 2000 as the first year of the 21st century and the 3rd millennium, because of a tende ...

, ME and XP. Since the first version, Microsoft has released nine more upgrades for .NET Framework, seven of which have been released along with a new version of

Visual Studio Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including web site, websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development ...

. Two of these upgrades, .NET Framework 2.0 and 4.0, have upgraded

Common Language Runtime The Common Language Runtime (CLR), the virtual machine component of Microsoft .NET Framework, manages the execution of .NET programs. Just-in-time compilation converts the managed code (compiled intermediate language code) into machine instr ...

(CLR). New versions of .NET Framework replace older versions when the CLR version is the same. The .NET Framework family also includes two versions for mobile or

embedded device An embedded system is a specialized computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or Electronics, electronic syst ...

use. A reduced version of the framework, the .NET Compact Framework, is available on

Windows CE Windows CE, later known as Windows Embedded CE and Windows Embedded Compact, is a discontinued operating system developed by Microsoft for mobile and embedded devices. It was part of the Windows Embedded family and served as the software foun ...

platforms, including

Windows Mobile Windows Mobile is a discontinued mobile operating system developed by Microsoft for smartphones and personal digital assistants (PDA). Designed to be the portable equivalent of the Windows desktop OS in the emerging Mobile device, mobile/port ...

devices such as

smartphone A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...

s. Additionally, the .NET Micro Framework is targeted at severely resource-constrained devices. .NET Framework 4.8 was announced as the last major version of .NET Framework, with future work going into the rewritten and

cross-platform Within computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several Computing platform, computing platforms. Some ...

.NET Core platform (later, simply ''.NET''), which shipped as ''.NET 5'' in November 2020. However, .NET Framework 4.8.1 was released in August 2022.

Overview

.NET Framework 1.0

The first version of the .NET Framework was released on 15 January 2002 for

Windows 98 Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the second operating system in the 9x line, as the successor to Windows 95. It was Software ...

, ME, NT 4.0,

, and XP. Mainstream support for this version ended on 10 July 2007, and extended support ended on 14 July 2009, with the exception of Windows XP Media Center and

Tablet PC A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being computers ...

editions. On 19 June 2001, the tenth anniversary of the release of Visual Basic, .NET Framework 1.0 Beta 2 was released. .NET Framework 1.0 is supported on

, ME, NT 4.0 (with Service Pack 6a),

, XP, and Server 2003. Applications utilizing .NET Framework 1.0 will also run on computers with .NET Framework 1.1 installed, which supports additional operating systems.

Service Pack 1

The .NET Framework 1.0 Service Pack 1 was released on 19 March 2002.

Service Pack 2

.NET Framework 1.0 Service Pack 2 was released on 7 August 2002.

Service Pack 3

.NET Framework 1.0 Service Pack 3 was released on 30 August 2004.

.NET Framework 1.1

Version 1.1 is the first minor .NET Framework upgrade. It is available on its own as a redistributable package or in a

software development kit A software development kit (SDK) is a collection of software development tools in one installable package. They facilitate the creation of applications by having a compiler, debugger and sometimes a software framework. They are normally specific t ...

, and was published on 3 April 2003. It is also part of the second release of

Visual Studio .NET 2003 Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platforms ...

. This is the first version of the .NET Framework to be included as part of the Windows operating system, shipping with

Windows Server 2003 Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT ...

. Mainstream support for .NET Framework 1.1 ended on 14 October 2008, and extended support ended on 8 October 2013. .NET Framework 1.1 provides full

backward compatibility In telecommunications and computing, backward compatibility (or backwards compatibility) is a property of an operating system, software, real-world product, or technology that allows for interoperability with an older legacy system, or with Input ...

to version 1.0, except in rare instances where an application will not run because it checks the version number of a library. Changes in 1.1 include: * Built-in support for mobile

ASP.NET ASP.NET is a server-side web-application framework designed for web development to produce dynamic web pages. It was developed by Microsoft to allow programmers to build dynamic web sites, applications and services. The name stands for Ac ...

controls, which was previously available as an add-on * Enables Windows Forms assemblies to execute in a semi-trusted manner from the Internet * Enables

Code Access Security Code Access Security (CAS), in the Microsoft .NET framework, is Microsoft's solution to prevent untrusted code from performing privileged actions. When the CLR loads an assembly it will obtain evidence for the assembly and use this to identify th ...

in ASP.NET applications * Built-in support for

ODBC In computing, Open Database Connectivity (ODBC) is a standard application programming interface (API) for accessing database management systems (DBMS). The designers of ODBC aimed to make it independent of database systems and operating systems. An ...

and

Oracle Database Oracle Database (commonly referred to as Oracle DBMS, Oracle Autonomous Database, or simply as Oracle) is a proprietary multi-model database management system produced and marketed by Oracle Corporation. It is a database commonly used for ru ...

, which was previously available as an add-on * .NET Compact Framework, a version of the .NET Framework for small devices * Internet Protocol version 6 (

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...

) support .NET Framework 1.1 is supported on

, ME, NT 4.0 (with Service Pack 6a),

, XP, Server 2003,

Vista Vista may refer to: Software *Windows Vista, the line of Microsoft Windows client operating systems released in 2006 and 2007 * VistA, (Veterans Health Information Systems and Technology Architecture) a medical records system of the United States ...

, and Server 2008.

Service Pack 1

The .NET Framework 1.1 Service Pack 1 was released on 30 August 2004. It requires

SP6a plus

Windows Installer Windows Installer (msiexec.exe, previously known as Microsoft Installer, List of Microsoft codenames, codename Darwin) is a software component and application programming interface (API) of Microsoft Windows used for the Installation (computer ...

2.0. It is the last version to support

SP6a,

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft, targeting the server and business markets. It is the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RT ...

RTM-SP2 and

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...

RTM-SP1.

.NET Framework 2.0

Version 2.0 was released on 27 October 2005. It was also released along with

Visual Studio 2005 Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including web site, websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development ...

Microsoft SQL Server 2005 The history of Microsoft SQL Server begins with the first Microsoft SQL Server database product – SQL Server v1.0, a 16-bit relational database for the OS/2 operating system, released in 1989. Versions Detailed history Genesis By the late ...

, and

BizTalk Microsoft BizTalk Server is an inter-organizational middleware system (IOMS) that automates business processes through the use of ''adapters'' which are tailored to communicate with different software systems used in an enterprise. Created by M ...

2006. A software development kit for this version was released on 29 November 2006. Support ended on 12 July 2011. It is the last version to support

SP3,

Windows ME Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...

and

RTM. Changes in 2.0 include: * Full

64-bit computing In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, ...

support for both the

x64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new operating modes: 64-bit mode an ...

and the

IA-64 IA-64 (Intel Itanium architecture) is the instruction set architecture (ISA) of the discontinued Itanium family of 64-bit Intel microprocessors. The basic ISA specification originated at Hewlett-Packard (HP), and was subsequently implemented by ...

hardware platforms *

Microsoft SQL Server Microsoft SQL Server is a proprietary relational database management system developed by Microsoft using Structured Query Language (SQL, often pronounced "sequel"). As a database server, it is a software product with the primary function of ...

integration: Instead of using

T-SQL Transact-SQL (T-SQL) is Microsoft's and Sybase's proprietary extension to the SQL (Structured Query Language) used to interact with relational databases. T-SQL expands on the SQL standard to include procedural programming, local variables, variou ...

, one can build

stored procedures A stored procedure (also termed prc, proc, storp, sproc, StoPro, StoredProc, StoreProc, sp, or SP) is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database da ...

and triggers in any of the .NET-compatible languages * A new hosting API for native applications wishing to host an instance of the .NET runtime: The new API gives a fine grain control on the behavior of the runtime with regards to multithreading, memory allocation and assembly loading. It was initially developed to efficiently host the runtime in

, which implements its own scheduler and memory manager. * New personalization features for

, such as support for themes, skins, master pages and webparts * .NET Micro Framework, a version of the .NET Framework related to the

Smart Personal Objects Technology The Smart Personal Objects Technology (SPOT) is a discontinued initiative by Microsoft to create intelligent and personal home appliances, consumer electronics, and other objects through new hardware capabilities and software features. Developme ...

initiative * Membership provider *

Partial class In object-oriented programming, a class defines the shared aspects of objects created from the class. The capabilities of a class differ between programming languages, but generally the shared aspects consist of state ( variables) and behavior ( ...

es *

Nullable type Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type. In statically typed languages, a nullable type is an option type, while i ...

s *

Anonymous method In computer programming, an anonymous function (function literal, expression or block) is a function definition that is not bound to an identifier. Anonymous functions are often arguments being passed to higher-order functions or used for constru ...

s *

Iterator In computer programming, an iterator is an object that progressively provides access to each item of a collection, in order. A collection may provide multiple iterators via its interface that provide items in different orders, such as forwards ...

s * Data tables *

(CLR) 2.0 * Language support for generics built directly into the .NET CLR .NET Framework 2.0 is supported on

, ME,

(with Service Pack 3 or higher), XP (with Service Pack 2 or higher), Server 2003, Server 2008 and

Server 2008 R2 Windows Server 2008 R2, codenamed "Windows Server 7" or "Windows Server 2008 Release 2", is the eighth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was released t ...

. Applications utilizing .NET Framework 2.0 will also run on computers with .NET Framework 3.0 or 3.5 installed, which supports additional operating systems.

Service Pack 1

The .NET Framework 2.0 Service Pack 1 was released on 19 November 2007. It requires Windows 2000 with SP4.

Service Pack 2

The .NET Framework 2.0 Service Pack 2 was released on 11 August 2008. It requires Windows 2000 with SP4 plus KB835732 or KB891861 update,

with SP2 plus

3.1. It is the last version to support

SP4 although there have been some unofficial workarounds to use a subset of the functionality from Version 3.5 in Windows 2000.

.NET Framework 3.0

.NET Framework 3.0, formerly called WinFX, was released on 6 November 2006. It includes a new set of

APIs that are an integral part of

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...

and

Windows Server 2008 Windows Server 2008, codenamed "Longhorn Server" (alternatives: "Windows Vista Server" or "Windows Server Vista"), is the seventh major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server b ...

. It is also available for

SP2 and

as a download. There are no major architectural changes included with this release; .NET Framework 3.0 uses the same CLR as .NET Framework 2.0. Unlike the previous major .NET releases there was no .NET Compact Framework release made as a counterpart of this version. Version 3.0 of the .NET Framework shipped with Windows Vista. It also shipped with Windows Server 2008 as an optional component (disabled by default). .NET Framework 3.0 consists of four major new components: *

Windows Presentation Foundation Windows Presentation Foundation (WPF) is a free and open-source user interface framework for Windows-based desktop applications. WPF applications are based in .NET, and are primarily developed using C# and XAML. Originally developed by Microso ...

(WPF), formerly code-named Avalon: A new

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine fro ...

subsystem and

API An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...

based on

XAML Extensible Application Markup Language (XAML ) is a declarative XML-based language developed by Microsoft for initializing structured values and objects. It is available under Microsoft's Open Specification Promise. XAML is used extensively i ...

markup language, which uses

3D computer graphics 3D computer graphics, sometimes called Computer-generated imagery, CGI, 3D-CGI or three-dimensional Computer-generated imagery, computer graphics, are graphics that use a three-dimensional representation of geometric data (often Cartesian coor ...

hardware and

Direct3D Direct3D is a graphics application programming interface (API) for Microsoft Windows. Part of DirectX, Direct3D is used to render three-dimensional graphics in applications where performance is important, such as games. Direct3D uses hardware ...

technologies *

Windows Communication Foundation The Windows Communication Foundation (WCF), previously known as Indigo, is a free and open-source runtime and a set of APIs in the .NET Framework for building connected, service-oriented applications. .NET Core 1.0, released 2016, did not s ...

(WCF), formerly code-named Indigo: A service-oriented messaging system which allows programs to interoperate locally or remotely similar to

web service A web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the Internet, or * a server running on a computer device, listening for requests at a particular port over a n ...

s *

Windows Workflow Foundation Windows Workflow Foundation (WF) is a Microsoft technology that provides an API, an in-process workflow engine, and a rehostable designer to implement long-running processes as workflows within .NET applications. The latest version of WF was re ...

(WF): Allows building task automation and integrated transactions using

workflow Workflow is a generic term for orchestrated and repeatable patterns of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a seque ...

s *

Windows CardSpace Windows CardSpace (codenamed InfoCard) is a discontinued identity selector app by Microsoft. It stores references to digital identities of the users, presenting them as visual information cards. CardSpace provides a consistent UI designed to ...

, formerly code-named InfoCard: A software component which securely stores a person's digital identities and provides a unified

interface Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Inter ...

for choosing the identity for a particular transaction, such as logging into a website .NET Framework 3.0 is supported on

, Server 2003,

, Server 2008, and

. Applications utilizing .NET Framework 3.0 will also run on computers with .NET Framework 3.5 installed, which supports additional operating systems.

Service Pack 1

.NET Framework 3.0 Service Pack 1 was released on 19 November 2007.

Service Pack 2

.NET Framework 3.0 Service Pack 2 was released on 11 August 2008.

.NET Framework 3.5

Version 3.5 of the .NET Framework was released on 19 November 2007. As with .NET Framework 3.0, version 3.5 uses Common Language Runtime (CLR) 2.0, that is, the same version as .NET Framework version 2.0. In addition, .NET Framework 3.5 also installs .NET Framework 2.0 SP1 and 3.0 SP1 (with the later 3.5 SP1 instead installing 2.0 SP2 and 3.0 SP2), which adds some methods and properties to the BCL classes in version 2.0 which are required for version 3.5 features such as Language Integrated Query (LINQ). These changes do not affect applications written for version 2.0, however. As with previous versions, a new .NET Compact Framework 3.5 was released in tandem with this update in order to provide support for additional features on Windows Mobile and

Windows Embedded CE Windows CE, later known as Windows Embedded CE and Windows Embedded Compact, is a discontinued operating system developed by Microsoft for mobile and embedded devices. It was part of the Windows Embedded family and served as the software foun ...

devices. The source code of the

Framework Class Library The Framework Class Library (FCL) is a component of Microsoft's .NET Framework, the first implementation of the Common Language Infrastructure (CLI). In much the same way as Common Language Runtime (CLR) implements the CLI Virtual Execution Sys ...

in this version has been partially released (for debugging reference only) under the Microsoft Reference Source License. .NET Framework 3.5 is supported on

(with Service Pack 2 or higher), Server 2003 (with Service Pack 1 or higher),

, Server 2008, 7,

, 8, Server 2012, 8.1, Server 2012 R2, 10, and Server 2016. Starting from Windows 8, .NET Framework 3.5 is an optional feature that can be turned on or off in control panel. .NET Framework 3.5 is also available as a Windows

Container A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping. Things kept inside of a container are protected on several sides by being inside of its structure. The term ...

image, allowing old applications that rely on .NET Framework 2.0–3.5 to run in a

container A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping. Things kept inside of a container are protected on several sides by being inside of its structure. The term ...

environment.

Service Pack 1

The .NET Framework 3.5 Service Pack 1 was released on 11 August 2008. This release adds new functionality and provides performance improvements under certain conditions, especially with WPF where 20–45% improvements are expected. Two new data service components have been added, the

ADO.NET Entity Framework Entity Framework (EF) is an open source object–relational mapping (ORM) framework for ADO.NET. It was originally shipped as an integral part of .NET Framework, however starting with Entity Framework version 6.0 it has been delivered separatel ...

and

ADO.NET Data Services WCF Data Services (formerly ADO.NET Data Services, codename "Astoria") is a platform for what Microsoft calls ''Data Services''. It is actually a combination of the runtime and a web service through which the services are exposed. It also include ...

. Two new assemblies for web development, System.WebAbstraction and System.WebRouting, have been added; these are used in the

ASP.NET MVC ASP.NET MVC is a web application framework developed by Microsoft that implements the model–view–controller (MVC) pattern. It is no longer in active development. It is open-source software, apart from the ASP.NET Web Forms component, which is ...

framework and, reportedly, will be used in the future release of ASP.NET Forms applications. Service Pack 1 is included with

SQL Server 2008 The history of Microsoft SQL Server begins with the first Microsoft SQL Server database product – SQL Server v1.0, a 16-bit relational database for the OS/2 operating system, released in 1989. Versions Detailed history Genesis By the late ...

and Visual Studio 2008 Service Pack 1. It also featured a new set of controls called "Visual Basic Power Packs" which brought back Visual Basic controls such as "Line" and "Shape." Version 3.5 SP1 of the .NET Framework shipped with Windows 7. It also shipped with Windows Server 2008 R2 as an optional component (disabled by default). It is the last version to support

SP2,

SP1 and

RTM.

.NET Framework 3.5 SP1 Client Profile

For the .NET Framework 3.5 SP1 there is also a new variant of the .NET Framework, called the ".NET Framework Client Profile", which at 28 MB is significantly smaller than the full framework and only installs components that are the most relevant to

desktop A desktop traditionally refers to: * The surface of a desk (often to distinguish office appliances that fit on a desk, such as photocopiers and printers, from larger equipment covering its own area on the floor) Desktop may refer to various compu ...

applications. However, the Client Profile amounts to this size only if using the online installer on Windows XP SP2 when no other .NET Frameworks are installed or using

Windows Update Windows Update is a Microsoft service for the Windows 9x and Windows NT families of the Microsoft Windows operating system, which automates downloading and installing Microsoft Windows software updates over the Internet. The service delivers sof ...

. When using the off-line installer or any other OS, the download size is still 250 MB.

.NET Framework 4.0

Key focuses for this release are: *

Parallel Extensions Parallel Extensions was the development name for a managed concurrency library developed by a collaboration between Microsoft Research and the CLR team at Microsoft. The library was released in version 4.0 of the .NET Framework. It is compos ...

to improve support for

parallel computing Parallel computing is a type of computing, computation in which many calculations or Process (computing), processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. ...

, which target

multi-core A multi-core processor (MCP) is a microprocessor on a single integrated circuit (IC) with two or more separate central processing units (CPUs), called ''cores'' to emphasize their multiplicity (for example, ''dual-core'' or ''quad-core''). Ea ...

distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

systems. To this end, technologies like PLINQ (Parallel

LINQ LinQ (pronounced "link") is a Japanese girl group. Their name stands for "Love in Qshu", in reference to their hometown of Fukuoka, on the island of Kyushu. Members The members were formerly divided into two groups, Qty and Lady. Current *Yuumi ...

), a parallel implementation of the LINQ engine, and

Task Parallel Library Parallel Extensions was the development name for a Managed code, managed Concurrent programming, concurrency Library (computing), library developed by a collaboration between Microsoft Research and the Common Language Runtime, CLR team at Microso ...

, which exposes parallel constructs via method calls, are included. * New

Visual Basic .NET Visual Basic (VB), originally called Visual Basic .NET (VB.NET), is a multi-paradigm, object-oriented programming language developed by Microsoft and implemented on .NET, Mono, and the .NET Framework. Microsoft launched VB.NET in 2002 as the ...

and C# language features, such as implicit line continuations,

dynamic dispatch In computer science, dynamic dispatch is the process of selecting which implementation of a polymorphic operation (method or function) to call at run time. It is commonly employed in, and considered a prime characteristic of, object-oriented ...

named parameter In computer programming, named parameters, named-parameter arguments, named arguments or keyword arguments refer to a computer language's support for function calls to clearly associate each argument with a given parameter within the function cal ...

s, and optional parameters * Support for Code Contracts * Inclusion of new types to work with

arbitrary-precision arithmetic In computer science, arbitrary-precision arithmetic, also called bignum arithmetic, multiple-precision arithmetic, or sometimes infinite-precision arithmetic, indicates that calculations are performed on numbers whose digits of precision are po ...

(System.Numerics.BigInteger) and

complex number In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the for ...

s (System.Numerics.Complex) * Introduced Common Language Runtime (CLR) 4.0 .NET Framework 4.0 is supported on

(with Service Pack 3),

(with Service Pack 2),

(with Service Pack 1 or higher), Server 2008, 7 and

. Applications utilizing .NET Framework 4.0 will also run on computers with .NET Framework 4.5 or 4.6 installed, which supports additional operating systems. Support for .NET Framework 4.0 ended on 12 April 2016 and is no longer providing technical support, bug fixes, or security fixes for .NET Framework 4.0 vulnerabilities which may be subsequently reported or discovered. It is the last version to support

SP3,

SP2,

SP1,

RTM,

Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...

RTM and

Windows Server 2008 R2 Windows Server 2008 R2, codenamed "Windows Server 7" or "Windows Server 2008 Release 2", is the eighth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was release ...

RTM.

History

Microsoft announced the intention to ship .NET Framework 4 on 29 September 2008. The Public Beta was released on 20 May 2009. On 28 July 2009, a second release of the .NET Framework 4 beta was made available with experimental

software transactional memory In computer science, software transactional memory (STM) is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. It is an alternative to lock-based synchronization. ST ...

support. This functionality is not available in the final version of the framework. On 19 October 2009, Microsoft released Beta 2 of the .NET Framework 4. At the same time, Microsoft announced the expected launch date for .NET Framework 4 as 22 March 2010. This launch date was subsequently delayed to 12 April 2010. On 10 February 2010, a

release candidate The software release life cycle is the process of developing, testing, and distributing a software product (e.g., an operating system). It typically consists of several stages, such as pre-alpha, alpha, beta, and release candidate, before the fi ...

was published. On 12 April 2010, the final version of .NET Framework 4.0 was launched alongside the final release of

Microsoft Visual Studio 2010 Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platforms ...

. On 18 April 2011, version 4.0.1 was released supporting some customer-demanded fixes for

. Its design-time component, which requires Visual Studio 2010 SP1, adds a workflow state machine designer. On 27 October 2011, version 4.0.2 was released supporting some new features of

. On 5 March 2012, version 4.0.3 was released.

Windows Server AppFabric

After the release of the .NET Framework 4, Microsoft released a set of enhancements, named Windows Server AppFabric, for

application server An application server is a server that hosts applications or software that delivers a business application through a communication protocol. For a typical web application, the application server sits behind the web servers. An application ser ...

capabilities in the form of AppFabric Hosting and in-memory distributed caching support.

.NET Framework 4.5

.NET Framework 4.5 was released on 15 August 2012; a set of new or improved features were added into this version. NET Framework 4.5 is supported on

or later. The .NET Framework 4.5 uses Common Language Runtime 4.0, with some additional runtime features. .NET Framework 4.5 is supported on

(with Service Pack 2), Server 2008 (with Service Pack 2), 7 (with Service Pack 1),

(with Service Pack 1), 8, Server 2012, 8.1 and Server 2012 R2. Applications utilizing .NET Framework 4.5 will also run on computers with .NET Framework 4.6 installed, which supports additional operating systems.

.NET for Metro-style apps

Metro-style app Universal Windows Platform (UWP) apps (formerly named Windows Store apps, Metro-style apps and Modern apps) are applications that can be used across all compatible Microsoft Windows devices. They are primarily purchased and downloaded via the ...

s were originally designed for specific form factors and leverage the power of the Windows operating system. Two subset of the .NET Framework is available for building Metro-style apps using C# or

Visual Basic Visual Basic is a name for a family of programming languages from Microsoft. It may refer to: * Visual Basic (.NET), the current version of Visual Basic launched in 2002 which runs on .NET * Visual Basic (classic), the original Visual Basic suppo ...

: One for

Windows 8 Windows 8 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on August 1, 2012, made available for download via Microsoft ...

and

Windows 8.1 Windows 8.1 is a release of the Windows NT operating system developed by Microsoft. It was released to manufacturing on August 27, 2013, and broadly released for retail sale on October 17, 2013, about a year after the retail release of its pr ...

, called ''.NET APIs for Windows 8.x Store apps''. Another for

Universal Windows Platform Universal Windows Platform (UWP) is a computing platform created by Microsoft and introduced in Windows 10. The purpose of this platform is to help develop universal apps that run on Windows 10, Windows 10 Mobile (discontinued), Windows 11, Xbox ...

(UWP), called ''.NET APIs for UWP''. This version of .NET Framework, as well as the runtime and libraries used for Metro-style apps, is a part of

Windows Runtime Windows Runtime (WinRT) is a platform-agnostic component and application architecture first introduced in Windows 8 and Windows Server 2012 in 2012. It is implemented in C++ and officially supports development in C++ (via C++/WinRT, C++/CX ...

, the new platform and development model for Metro-style apps. It is an ecosystem that houses many platforms and languages, including .NET Framework, C++ and

HTML5 HTML5 (Hypertext Markup Language 5) is a markup language used for structuring and presenting hypertext documents on the World Wide Web. It was the fifth and final major HTML version that is now a retired World Wide Web Consortium (W3C) recommend ...

with

JavaScript JavaScript (), often abbreviated as JS, is a programming language and core technology of the World Wide Web, alongside HTML and CSS. Ninety-nine percent of websites use JavaScript on the client side for webpage behavior. Web browsers have ...

Core features

* Ability to limit how long the

regular expression A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...

engine will attempt to resolve a regular expression before it times out. * Ability to define the culture for an

application domain An application domain is a mechanism (similar to a process in an operating system) used within the Common Language Infrastructure (CLI) to isolate executed software applications from one another so that they do not affect each other. Each applicat ...

. * Console support for

Unicode Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...

(

UTF-16 UTF-16 (16-bit Unicode Transformation Format) is a character encoding that supports all 1,112,064 valid code points of Unicode. The encoding is variable-length as code points are encoded with one or two ''code units''. UTF-16 arose from an earli ...

) encoding. * Support for versioning of cultural string ordering and comparison data. * Better performance when retrieving resources. * Native support for Zip compression (previous versions supported the compression algorithm, but not the archive format). * Ability to customize a

reflection context Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, mirror-like reflection of waves from a surface *** Mirror image, a reflection in a mirror or in water ** Diffuse r ...

to override default

reflection Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, mirror-like reflection of waves from a surface *** Mirror image, a reflection in a mirror or in water ** Diffuse r ...

behavior through the CustomReflectionContext class. * New asynchronous features were added to the C# and

languages. These features add a task-based model for performing asynchronous operations, implementing

futures and promises In computer science, futures, promises, delays, and deferreds are constructs used for synchronization (computer science), synchronizing program execution (computing), execution in some concurrent programming languages. Each is an object that act ...

Managed Extensibility Framework (MEF)

The Managed Extensibility Framework or MEF is a library for creating lightweight, extensible applications. It allows application developers to discover and use extensions with no configuration required. It also lets extension developers easily encapsulate code and avoid fragile hard dependencies. MEF not only allows extensions to be reused within applications, but across applications as well.

ASP.NET

* Support for new

form types. * Support for model binders in

Web Forms ASP.NET is a server-side scripting, server-side web-application framework designed for web development to produce dynamic web pages. It was developed by Microsoft to allow programmers to build dynamic web sites, web application, applications a ...

. These let you bind data controls directly to data-access methods, and automatically convert user input to and from .NET Framework

data type In computer science and computer programming, a data type (or simply type) is a collection or grouping of data values, usually specified by a set of possible values, a set of allowed operations on these values, and/or a representation of these ...

s. * Support for unobtrusive

in client-side validation scripts. * Improved handling of client script through bundling and minification for improved page performance. * Integrated encoding routines from the Anti-XSS library (previously an external library) to protect from

cross-site scripting Cross-site scripting (XSS) is a type of security vulnerability that can be found in some web applications. XSS attacks enable attackers to inject client-side scripts into web pages viewed by other users. A cross-site scripting vulnerability may be ...

attacks. * Support for

WebSocket WebSocket is a computer communications protocol, providing a full-duplex, simultaneous two-way communication channel over a single Transmission Control Protocol (TCP) connection. The WebSocket protocol was standardized by the Internet Engineering ...

protocol. * Support for reading and writing

HTTP HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, wher ...

requests and responses asynchronously. * Support for asynchronous modules and handlers. * Support for

content distribution network A content delivery network (CDN) or content distribution network is a geographically distributed network of proxy servers and their data centers. The goal is to provide high availability and performance ("speed") by distributing the service spat ...

(CDN) fallback in the ScriptManager control.

Networking

* Provides a new

programming interface An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build su ...

for HTTP applications: System.NetHttp namespace and System.Net.HttpHeaders namespaces are added * Improved

internationalization Internationalization or Internationalisation is the process of increasing involvement of enterprises in international markets, although there is no agreed definition of internationalization. Internationalization is a crucial strategy not only for ...

and

support * RFC-compliant

URI Uri may refer to: Places * Canton of Uri, a canton in Switzerland * Úri, a village and commune in Hungary * Uri, Iran, a village in East Azerbaijan Province * Uri, Jammu and Kashmir, a town in India * Uri (island), off Malakula Island in V ...

support * Support for

internationalized domain name An internationalized domain name (IDN) is an Internet domain name that contains at least one label displayed in software applications, in whole or in part, in non-Latin script or alphabet or in the Latin alphabet-based characters with diacrit ...

(IDN) parsing * Support for

Email Address Internationalization An email address identifies an email box to which messages are delivered. While early messaging systems used a variety of formats for addressing, today, email addresses follow a set of specific rules originally standardized by the Internet Engineeri ...

(EAI)

.NET Framework 4.5.1

The release of .NET Framework 4.5.1 was announced on 17 October 2013 along Visual Studio 2013. This version requires Windows Vista SP2 and later and is included with

and

Windows Server 2012 R2 Windows Server 2012 R2, codenamed "Windows Server Blue", is the tenth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was unveiled on June 3, 2013, at TechEd Nort ...

. New features of .NET Framework 4.5.1: * Debugger support for X64 edit and continue (EnC) * Debugger support for seeing managed return values * Async-aware debugging in the Call Stack and Tasks windows * Debugger support for analyzing .NET memory dumps (in the Visual Studio Ultimate SKU) * Tools for .NET developers in the Performance and Diagnostics hub * Code Analysis UI improvements * ADO.NET idle connection resiliency

.NET Framework 4.5.2

The release of .NET Framework 4.5.2 was announced on 5 May 2014. This version requires Windows Vista SP2 and later. For

Windows Forms Windows Forms, also known as WinForms, is a free, open-source graphical user interface (GUI) class library for building Windows desktop applications, included as a part of Microsoft .NET, .NET Framework or Mono, providing a platform to write c ...

applications, improvements were made for high

DPI DPI may refer to: Organizations * Department of Public Information, related to U.N. *Daffodil Polytechnic Institute, an educational institution of Bangladesh * Dhaka Polytechnic Institute, an educational institution of Bangladesh * Disabled Peop ...

scenarios. For ASP.NET, higher reliability HTTP header inspection and modification methods are available as is a new way to schedule background asynchronous worker tasks.

.NET Framework 4.6

.NET Framework 4.6 was announced on 12 November 2014. It was released on 20 July 2015. It supports a new

just-in-time compiler In computing, just-in-time (JIT) compilation (also dynamic translation or run-time compilations) is compiler, compilation (of Source code, computer code) during execution of a program (at run time (program lifecycle phase), run time) rather than b ...

(JIT) for 64-bit systems called RyuJIT, which features higher performance and support for

SSE2 SSE2 (Streaming SIMD Extensions 2) is one of the Intel SIMD (Single Instruction, Multiple Data) processor supplementary instruction sets introduced by Intel with the initial version of the Pentium 4 in 2000. SSE2 instructions allow the use of ...

and

AVX2 Advanced Vector Extensions (AVX, also known as Gesher New Instructions and then Sandy Bridge New Instructions) are SIMD extensions to the x86 instruction set architecture for microprocessors from Intel and Advanced Micro Devices (AMD). They w ...

instruction sets. WPF and Windows Forms both have received updates for high DPI scenarios. Support for TLS 1.1 and TLS 1.2 has been added to WCF. This version requires

SP2 or later. It is the last version to support

SP2 and

SP2. The cryptographic API in .NET Framework 4.6 uses the latest version of Windows CNG cryptography API. As a result,

NSA Suite B Cryptography NSA Suite B Cryptography was a set of cryptographic algorithms promulgated by the National Security Agency as part of its Cryptographic Modernization Program. It was to serve as an interoperable cryptographic base for both unclassified informat ...

is available to .NET Framework. Suite B consists of AES, the

SHA-2 SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression ...

family of hashing algorithms,

elliptic curve Diffie–Hellman In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in ...

, and

elliptic curve DSA In cryptography, the Elliptic Curve Digital Signature Algorithm (ECDSA) offers a variant of the Digital Signature Algorithm (DSA) which uses elliptic-curve cryptography. Key and signature sizes As with elliptic-curve cryptography in general, the ...

. .NET Framework 4.6 is supported on

(with Service Pack 2), Server 2008 (with Service Pack 2), 7 (with Service Pack 1),

(with Service Pack 1), 8, Server 2012, 8.1, Server 2012 R2, 10 and Server 2016. Support for .NET Framework 4.6 ended on 26 April 2022.

.NET Framework 4.6.1

The release of .NET Framework 4.6.1 was announced on 30 November 2015. This version requires

SP1 or later and is also the last version to support

. New features and APIs include: * WPF improvements for spell check, support for per-user custom dictionaries and improved touch performance. * Enhanced support for Elliptic Curve Digital Signature Algorithm (ECDSA) X509 certificates. * Added support in SQL Connectivity for AlwaysOn, Always Encrypted and improved connection open resiliency when connecting to Azure SQL Database. * Azure SQL Database now supports distributed transactions using the updated System.Transactions APIs . * Many other performance, stability, and reliability related fixes in RyuJIT, GC, WPF and WCF.

.NET Framework 4.6.2

The preview of .NET Framework 4.6.2 was announced on 30 March 2016. It was released on 2 August 2016. This version requires

SP1 or later and is also the last version to support

Windows 10 Windows 10 is a major release of Microsoft's Windows NT operating system. The successor to Windows 8.1, it was Software release cycle#Release to manufacturing (RTM), released to manufacturing on July 15, 2015, and later to retail on July 2 ...

(RTM—1511). New features include: * Support for paths longer than 260 characters * Support for FIPS 186-3 DSA in

X.509 In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secure ...

certificates * TLS 1.1/1.2 support for

ClickOnce ClickOnce is a component of Microsoft .NET Framework 2.0 and later, and supports deploying applications made with Windows Forms or Windows Presentation Foundation. It is similar to Java Web Start for the Java Platform or Zero Install for Linu ...

* Support for localization of data annotations in ASP.NET * Enabling .NET desktop apps with Project Centennial * Soft keyboard and per-monitor DPI support for WPF .NET Framework 4.6.2 is also shipped as Windows container image.

.NET Framework 4.7

On 5 April 2017, Microsoft announced that .NET Framework 4.7 was integrated into

Windows 10 Creators Update Windows 10 Creators Update (also known as version 1703 and codenamed "Redstone 2") is the third major update to Windows 10 and the second in a series of updates under the Redstone codenames. It carries the build number 10.0.15063. PC version his ...

, promising a standalone installer for other Windows versions. An update for

Visual Studio 2017 Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platforms ...

was released on this date to add support for targeting .NET Framework 4.7. The promised standalone installer for Windows 7 and later was released on 2 May 2017, but it had prerequisites not included with the package. NET Framework 4.7 dropped support for

and will only run on Windows 7 Service Pack 1 and later. New features in .NET Framework 4.7 include: * Enhanced cryptography with

elliptic curve cryptography Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys to provide equivalent security, compared to cryptosystems based on modula ...

* Improve TLS support, especially for version 1.2 * High-DPI awareness support in Windows Forms * More support for touch and stylus in Windows Presentation Foundation (WPF) * New print APIs for WPF .NET Framework 4.7 is supported on

(with Service Pack 1),

(with Service Pack 1), Server 2012, 8.1, Server 2012 R2, 10, Server 2016 and Server 2019. .NET Framework 4.7 is also shipped as a Windows container image.

.NET Framework 4.7.1

.NET Framework 4.7.1 was released on 17 October 2017. Amongst the fixes and new features, it corrects a d3dcompiler dependency issue. It also adds compatibility with the .NET Standard 2.0 out of the box. .NET Framework 4.7.1 is also shipped as a Windows container image.

.NET Framework 4.7.2

.NET Framework 4.7.2 was released on 30 April 2018. Amongst the changes are improvements to ASP.NET, BCL, CLR, ClickOnce, Networking, SQL, WCF, Windows Forms, Workflow and WPF. This version is included with Server 2019. .NET Framework 4.7.2 is also shipped as a Windows container image.

.NET Framework 4.8

.NET Framework 4.8 was released on 18 April 2019. It was the final version of .NET Framework released after

reached end of life on 11 April 2017, with future work going into the .NET Core platform that eventually became .NET 5 and onwards. This release included JIT enhancements ported from .NET Core 2.1, High DPI enhancements for WPF applications, accessibility improvements, performance updates, and security enhancements. Over five months after its release, an update for Visual Studio 2019 was released on 23 September 2019 to add support for targeting .NET Framework 4.8. It supported

(with Service Pack 1),

(with Service Pack 1), Server 2012, 8.1, Server 2012 R2, 10, Server 2016 and Server 2019 and also shipped as a Windows container image. It is the last version to support

SP1,

Windows Server 2012 Windows Server 2012, codenamed "Windows Server 8", is the ninth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It is the server version of Windows based on Windows ...

(1607–1809),

Windows Server 2016 Windows Server 2016 is the eleventh major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was developed alongside Windows 10 and is the successor to the Windows 8.1-based ...

and

Windows Server 2019 Windows Server 2019 is the twelfth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It is the second version of the server operating system based on the Windows 10 plat ...

, although it is only supported as included in Windows 10 (1903–2004). The most-recent release is 4.8.0 Build 4115, with an offline installer size of 115 MB (121,307,088 bytes) and a digital signature date of May 1, 2021.

.NET Framework 4.8.1

.NET Framework 4.8.1 was released on 9 August 2022. This version includes the native

ARM64 AArch64, also known as ARM64, is a 64-bit version of the ARM architecture family, a widely used set of computer processor designs. It was introduced in 2011 with the ARMv8 architecture and later became part of the ARMv9 series. AArch64 allows ...

support, WCAG2.1 compliant accessible tooltips, and accessibility improvements for Windows Forms. It is supported on

(20H2–22H2),

Windows Server 2022 Windows Server 2022 is the thirteenth major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was announced at Microsoft's Ignite event from March 2–4, 2021. It was rele ...

and

Windows 11 Windows 11 is a version of Microsoft's Windows NT operating system, released on October 5, 2021, as the successor to Windows 10 (2015). It is available as a free upgrade for devices running Windows 10 that meet the #System requirements, Windo ...

. The most-recent release is 4.8.1 Build 9195, with an offline installer size of 74 MB (77,668,504 bytes) and a digital signature date of September 28, 2023.

References

{{.NET Framework 2002 software Microsoft application programming interfaces Microsoft development tools Software version histories