Applies To.NET

Release Date:March 26, 2024

Version: .NET Framework 3.5 and 4.8.1

The March 26, 2024 update for Windows 11, version 22H2 includes security and cumulative reliability improvements in .NET Framework 3.5 and 4.8.1. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.

Summary

Security Improvements

There are no new security improvements in this release. This update is cumulative and contains all previously released security improvements.

Quality and Reliability Improvements

There are no new Quality and Reliability Improvements in this update.

.NET Libraries

- Addresses a performance issue in ASP.NET applications after installing the January 2024 .NET Framework update.

.NET Runtime

- Addresses an issue when thread pool recycled lists become unresponsive on multi-CPU-group computers.

- Addresses an issue where Interlocked.Read from 32-bit apps are much slower on some computers.

.NET Compilers

- Addresses an issue when using the native C# compiler (csc.exe) to compile code making calls to COM interop assemblies.

Known issues in this update

Microsoft is not currently aware of any issues in this update.

How to get this update

Install this update

Release Channel

Available

Next Step

Windows Update and Microsoft Update

Yes

Go to Settings > Update & Security > Windows Update. In the Optional updates available area, you’ll find the link to download and install the update.

Windows Update for Business

Yes

Go to Settings > Update & Security > Windows Update. In the Optional updates available area, you’ll find the link to download and install the update.

Microsoft Update Catalog

Yes

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Windows Server Update Services (WSUS)

No

You can import this update into WSUS manually. See the Microsoft Update Catalog for instructions.

File information

For a list of the files that are provided in this update, download the file information for cumulative update.

Prerequisites

To apply this update, you must have .NET Framework 3.5 or 4.8.1 installed.

Restart requirement

You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.

How to obtain help and support for this update

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