Today, we are releasing the July 2021 Cumulative Update Preview for .NET Framework.

Security

The July Cumulative Update Preview does not contain any new security fixes. See February 2021 Security and Quality Rollup for the latest security updates.

Quality and Reliability

This release contains the following quality and reliability improvements.

CLR¹

• In scenarios with both high numbers of assemblies and high numbers of GC heaps, Server GC can encounter serious lock contention during generation 2 GCs. A config switch has been introduced as a workaround. It can either be enabled from a .config file:

  <configuration>
    <runtime>
      <GCStaticsNoLock enabled="true"/>
    </runtime>
  </configuration>

  Or by setting environment variable COMPLUS_GCStaticsNoLockto a non-zero value. If the config switch is not enabled then behavior is unchanged compared to previous versions.

Windows Forms

• Addresses an issue where some Windows Forms applications that use ToolStrip controls with ToolStripControlHost, and run under UIA Accessibility Tools, could make Accessibility Tools unresponsive.
• Addresses a regression in the ComboBox item accessible object where Accessibility Tools was not able to distinguish between identical items in the ComboBox and was becoming unresponsive.

¹ Common Language Runtime (CLR)

Getting the Update

The Cumulative Update Preview is available via Windows Update and Microsoft Update Catalog.

Microsoft Update Catalog

You can get the update via the Microsoft Update Catalog.

**Note**: Customers that rely on Windows Update will automatically receive the .NET Framework version-specific updates. Advanced system administrators can use of the below direct Microsoft Update Catalog download links to .NET Framework version specific updates.  Carefully review the .NET Framework version applicability to ensure that you only install updates on systems where they apply before installing updates.

Previous Monthly Rollups

The last few updates are listed below for your convenience:

• • .NET Framework July 2021 Security and Quality Rollup
  • .NET Framework June 2021 Cumulative Update Preview
  • .NET Framework June 2021 Security and Quality Rollup Updates