If you have previously installed this update no action is needed. The September 26, 2023 update for Windows 10 Version 22H2 includes 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.

Summary. This article describes the security and Cumulative Update for 3.5, 4.8 and 4.8.1 for Windows 11, version 21H2. Security Improvements