Announcing Cumulative Updates for .NET Framework for Windows 10 October 2018 Update

Brett Lopez [MSFT]

We deliver .NET Framework updates nearly every month, through Windows Update and other distribution channels. We are making changes to the way that we deliver those updates. We’ll soon start delivering a Cumulative Update for .NET Framework alongside the Windows 10 Cumulative Update, starting with the Windows 10 October 2018 Update. This new approach will give you more flexibility on installing .NET Framework updates.

What is the new Cumulative Update for  .NET Framework?

Starting with Windows 10 October 2018 Update and Windows Server 2019, .NET Framework fixes will be delivered through a Cumulative Update for .NET Framework.

We are making this change to enable the following:

  • Provide more flexibility for installing .NET Framework updates (for example, IT Admins can more selectively test line of business applications before broadly deploying).
  • Ability to respond to critical customer needs, when needed, with higher velocity, with standalone .NET Framework patches.

The Cumulative Update for .NET Framework will have the following characteristics:

  • Independent – Released separately from the Windows Cumulative Update
  • Cumulative – The latest patch will fully update all .NET Framework versions on your system
  • Same cadence – The Cumulative Update for .NET Framework will be released on the same cadence as Windows 10.

What should I expect?

You can expect the following new experiences.

Windows Update users:

If you rely on Windows Update to keep your machine up to date and have automatic updates enabled, you will not notice any difference.  Updates for both Windows and the .NET Framework will be silently installed, and as usual you may be prompted for a reboot after installation.

If you manage Windows Update manually, you will notice a Cumulative Update for .NET Framework update alongside the Windows cumulative update. Please continue to apply the latest updates to keep your system up to date.

Image: Cumulative Update for .NET Framework delivered via Windows Update

You can continue to rely on existing guidance for advanced Windows Update settings.

Systems and IT Administrators:

  • System administrators relying on Windows Server Update Services (WSUS) and similar update management applications will observe a new update for .NET Framework when checking for updates applicable to upcoming versions of Windows 10 October 2018 Update and Windows Server 2019.
  • The Cumulative Update for .NET Framework Classifications remain the same as for the Cumulative Update for Windows and continue to show under the same Windows Products. Updates that deliver new Security content will carry the “Security Updates” classification and updates carrying solely new quality updates will carry either the “Updates” or “Critical Updates” classification, depending on their criticality.
  • System administrators that rely on the Microsoft Update Catalog will be able to access the Cumulative Update for .NET Framework by searching for each releases’ Knowledge Based (KB) update number. Note that a single update will contain fixes for both .NET Framework 3.5 and 4.7.2 products.
  • You can use the update title to filter between the Windows Cumulative updates and .NET Framework updates. All other update artifacts are expected to remain the same.

Image: Cumulative Update for .NET Framework delivered via WSUS Administration console

.NET Framework updates across Windows versions

.NET Framework updates will be delivered in the following way:

  • Windows 10 October 2018 Update (version 1809) and Windows Server 2019 – One Cumulative Update for .NET Framework, alongside the Windows Cumulative Update.
  • Windows 10 April 2018 (version 1803) and earlier versions of Windows 10, including Windows Server 2016 – One Windows Cumulative Update (which includes .NET Framework updates), per Windows version.
  • Windows 7 and 8.1 – Multiple .NET Framework updates, per Windows version.

.NET Framework updates are delivered on the same servicing cadence as Windows 10. We deliver different types of updates on different schedules, as described below.

  • The security and quality updates for .NET Framework will be released on Patch Tuesday, the second Tuesday of each month, containing important security and critical quality improvements.
  • Each new security and quality update will supersede and replace the last security and quality update release.
  • Preview updates for .NET Framework will be released one to two weeks after the Patch Tuesday release, for non-security fixes as a limited distribution release (will not be installed automatically).
  • Out-of-band releases are reserved for situations where customer systems must be updated quickly and outside of the regular schedule, to fix security vulnerabilities or to resolve critical quality issues.

For more information about .NET Framework update model for previous versions of Windows, please refer to: Introducing the .NET Framework Monthly Rollup and .NET Framework Monthly Rollups Explained.

Validating the Quality of Updates

We extensively validate the quality of these updates before publishing them. .NET Framework updates are installed by many customers on many machines. It is often the case for Patch Tuesday updates that they contain security updates and it is important that you can apply those quickly throughout your environment. We are continually improving our validation system to ensure high-quality updates.

We use the following approaches to validate quality:

  • Extensive functional testing with in-house regression tests.
  • Compatibility testing with Microsoft applications, servers and services.
  • Compatibility testing with third-party applications that have been submitted to the .NET Framework compatibility lab. You can submit your app at
  • Security Update Validation Program (SUVP).
  • Listen to customer feedback from previous preview releases and Windows Insider builds.



Will installing a Cumulative Update for .NET Framework upgrade my .NET Framework version?

No. These updates will not upgrade you to a new .NET Framework version. They will update the .NET Framework version you already have installed.

Will I need to reboot after installing the Cumulative Update for .NET Framework ?

In most cases, yes.

Will I need an additional reboot when installing the Cumulative Update for .NET Framework together with the Windows Cumulative update?

Windows Update will orchestrate making sure updates that ship at the same time are processed together and only require a single reboot. Guidance to WSUS/IT Admins is to continue to ensure that updates are grouped and deployed together to avoid any potential additional reboots.

Is there a security-only variant of the Cumulative Update for .NET Framework?

No. This approach limits the number of updates to manage and aligns with the model used by Windows 10.

What do I need to do to update .NET Framework 3.5?

Install the Cumulative Update for .NET Framework. It includes .NET Framework 3.5 fixes.

I have concerns about the quality of .NET Framework fixes. What can I do?

You can submit your application for testing in our compatibility lab (send mail to and install .NET Framework Preview of Quality updates to validate compatibility.

Is Microsoft producing new types of patches in addition to the new Cumulative Update for .NET Framework?

No new standalone updates are planned.