The deployment model of .NET Framework 3.5 for future versions of Windows is changing. Starting with Windows 11 Insider Preview Build 27965, .NET Framework 3.5 must be obtained as a standalone installer and is no longer included as an optional Windows component.

.NET Framework 3.5 is now available as a standalone installer for legacy applications that require it on newer major versions of Windows.

This change applies to Insider Preview Build 27965 and future platform releases of Windows. It does not affect Windows 10 or earlier Windows 11 releases through 25H2.

This change aligns with the product’s lifecycle as .NET Framework 3.5 approaches end of support on January 9, 2029, and encourages customers to begin planning migrations to newer supported versions of .NET.

If your application depends on .NET Framework 3.5, we’ve published detailed guidance—including installers, compatibility notes, and recommended migration paths—on Microsoft Learn.