Microsoft decouples .NET Framework 3.5 from Windows

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Microsoft has announced that the classic .NET Framework version 3.5 will no longer be part of the operating system setup in Windows 11 starting in 2026. Previously, .NET Framework 3.5 was an optional component during operating system installation.

Soon standalone installation

In the future, users will have to download the installer for .NET Framework 3.5 from the Microsoft website and run it separately. This change initially only affects Windows 11 starting with Insider Preview Build 27965, but is expected to be included in the stable Windows channel with the feature release 26H1.

This change is not planned for Windows 10. Microsoft explains details about the change in a short FAQ.

Support for .NET Framework 3.5 ends in 2029

The .NET Framework 3.5 was released on November 19, 2007. Support for this version ends on January 9, 2029, see Microsoft .NET Framework Lifecycle Policy. Version 3.5 is an older version of the classic .NET Framework, which had numerous successors in versions 4.0, 4.5, 4.6.x, 4.7.x, and 4.8.x.

Support for versions 4.0, 4.5, and 4.5.1 already ended in 2016. Versions 4.5.2, 4.6, and 4.6.1 went out of support in 2022. Version 4.6.2 will be retired on January 12, 2027.

No end of support for .NET Framework 4.7 to 4.8.1

No end of support has yet been announced for versions 4.7 to 4.8.1 of the classic .NET Framework. When introducing the modern .NET versions (initially as .NET Core in versions 1.0 to 3.1 in 2016, then only called .NET since version 5.0), Microsoft had officially stated that there would be no significant further development of the .NET Framework. However, after this statement in 2019, version 4.8.1 was still released in August 2022 for the classic .NET Framework.

Microsoft had also stated that they would continue to work on bug fixes, reliability, and security for the classic .NET Framework versions and that the .NET Framework would continue to be shipped with Windows. However, as the change in the delivery method of .NET Framework 3.5 now shows, this statement “part of Windows” apparently does not apply to all versions.

Current version .NET 10.0

The current version of modern .NET is version 10.0, which was released on November 11, 2025 – along with C# 14.0. The heise blog Der Dotnet-Doktor publishes a weekly article introducing new features in C# 14.0 and .NET 10.0.

Details about the transition of .NET Framework 3.5 can be found in the Microsoft blog.

(mki)