Windows monthly updates explained
Published Mar 21 2023 10:00 AM 457K Views

Windows updates keep you protected and productive in different ways, and we continue to optimize the update experience. Whether you're an IT administrator or a general user, Windows monthly updates provide you with the security fixes to help keep your devices protected—as well as enhancements based on your feedback. Monthly updates are cumulative and include all previously released fixes to guard against fragmentation of the operating system (OS). This contributes to the reliability and quality of the Windows platform.

This post summarizes the different types of monthly updates and shares insights on how we've optimized our approach to Windows servicing and delivery.

Monthly security update release

For many of you, Update Tuesday (also referred to as "Patch Tuesday") is a regular part of Windows servicing for client and server. Published on the second Tuesday of each month, our security update releases are cumulative. That is, they include both new and previously released security fixes along with non-security content introduced in the prior month's optional non-security preview release (see below). These updates help keep Windows devices secure and compliant by deploying stability fixes and addressing security vulnerabilities.


Note: People tend to use "B release," quality update, security update, and LCU interchangeably.

Monthly security updates are mandatory and are available through our standard channels, which include Windows Update, Windows Update for Business, Microsoft Intune, Microsoft Configuration Manager, Windows Server Update Services (WSUS), and the Microsoft Update Catalog.

Optional non-security preview release

You've got options with optional non-security preview releases. Available the fourth week of the month, these production-quality updates are released ahead of the planned security update release for the following month. In addition, new features, like Search highlights, may initially be deployed in the prior month's optional non-security preview release, then ship broadly in the following month's security release.


Note: The term “optional non-security preview release” now replaces what we used to call either a “C” or “D” release to align with the current process.

Optional non-security preview releases are also cumulative and are only offered for the most recent supported versions of Windows.

Editor’s note: As of March 21, 2023, the “most recent supported versions” refers to Windows 10, version 22H2 and Windows 11, versions 21H2 and 22H2.

Starting in April 2023, we now target optional non-security preview releases for the fourth week of the month. We have found this to be the optimal time for us to publish and for you to consume these updates. That's two weeks after your latest monthly security update and about two weeks before you'll see these features become part of the next mandatory cumulative update. We're excited for this improvement as it is meant to optimize the validation of payloads, improve consistency, and enhance the predictability of your testing, update, and upgrade experience.

To access optional non-security preview releases, navigate to Settings > Windows Update > Advanced options > Optional updates, select from the available updates, and click Download and install.

Out-of-band releases

Out-of-band (OOB) releases may be provided to fix a recently identified issue or vulnerability. They are used in atypical cases, such as security vulnerabilities or a quality issue, when devices should be updated immediately instead of waiting for the next monthly quality update release. Out-of-band releases are cumulative, meaning that they include the updates from the previous security and/or non-security release, as well as the additional fix.

Continuous innovation in Windows 11

Beginning with Windows 11, version 22H2, new features and enhancements are delivered to the most recently released in-market version of Windows 11 more frequently using servicing technology. As with all updates, we utilize a phased and measured approach in rolling out continuous innovation to the Windows 11 ecosystem.

Experiences may be introduced in an optional non-security preview release prior to being made available broadly via a monthly security update or via Controlled Feature Rollout (CFR) technology. For more information on how to control when select features introduced via servicing are released to the devices you manage, see Commercial control for continuous innovation.


As a general practice, we recommend that you update your devices as soon as possible, whether you're a general user or an IT professional. For IT admins, we also recommend taking advantage of the optional non-security preview releases to internally validate releases ahead of the following month's security update release.

To help manage updates across your organization, bookmark these resources:

These pages are available in multiple languages and refer to each release by a unique KB number.

IT admins may validate fixes and features in a preview release by leveraging the Windows Insider Program for Business or via the Microsoft Update Catalog.

If you are a Microsoft Partner or registered commercial customer, you can also take advantage of the Security Update Validation Program (SUVP). It's a quality assurance testing program designed for the monthly security update release. As a SUVP partner, you can start testing these security updates three weeks prior to Update Tuesday and provide us with feedback regarding usability, bug reports, test reports, etc.

For additional tips, read Ensuring a successful Windows quality update experience.

Continue the conversation. Find best practices. Bookmark the Windows Tech Community and follow us @MSWindowsITPro on Twitter. Looking for support? Visit Windows on Microsoft Q&A.

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‎Nov 09 2023 11:09 AM
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