Servicing stack updates
What is a servicing stack update?
Servicing stack updates provide fixes to the servicing stack, the component that installs Windows updates. Additionally, it contains the component-based servicing stack (CBS), which is a key underlying component for several elements of Windows deployment, such as DISM, SFC, changing Windows features or roles, and repairing components. CBS is a small component that typically doesn't have updates released every month.
Why should servicing stack updates be installed and kept up to date?
Servicing stack updates improve the reliability of the update process to mitigate potential issues while installing the latest quality updates and feature updates. If you don't have the latest servicing stack update installed, there's a risk that your device can't be updated with the latest Microsoft security fixes.
When are they released?
Servicing stack update are released depending on new issues or vulnerabilities. In rare occasions, a servicing stack update might need to be released out of band to address an issue impacting systems installing the monthly security update. New servicing stack updates are classified as Security with a severity rating of Critical.
What's the difference between a servicing stack update and a cumulative update?
Both Windows client and Windows Server use the cumulative update mechanism, in which many fixes to improve the quality and security of Windows are packaged into a single update. Each cumulative update includes the changes and fixes from all previous updates.
Servicing stack updates improve the reliability of the update process to mitigate potential issues while installing the latest monthly security update release and feature updates. If you don't install the latest servicing stack update, there's a risk that your device can't be updated with the latest Microsoft security fixes.
Microsoft publishes all cumulative updates and servicing stack updates for Windows 10, version 2004 and later together as one cumulative monthly update to the normal release category in Windows Server Update Services (WSUS).
Is there any special guidance?
Typically, the improvements are reliability and performance improvements that don't require any specific special guidance. If there's any significant impact, it will be present in the release notes.
Most users don't need to install an isolated servicing stack update. In the rare case that you need to install an isolated servicing stack update, Microsoft recommends you install the latest servicing stack updates for your operating system before installing the latest cumulative update.
Installation notes
- Servicing stack updates contain the full servicing stack; as a result, typically administrators only need to install the latest servicing stack update for the operating system.
- Installing servicing stack update doesn't require restarting the device, so installation shouldn't be disruptive.
- Servicing stack update releases are specific to the operating system version (build number), much like quality updates.
- Servicing stack updates can be delivered with Windows Update, or you can perform a search to install the latest available at Servicing stack update for Windows 10.
- Once a servicing stack update is installed, it can't be removed or uninstalled from the machine.
Simplifying on-premises deployment of servicing stack updates
With the Windows Update experience, servicing stack updates and cumulative updates are deployed together to the device. The update stack automatically orchestrates the installation, so both are applied correctly. Starting in February 2021, the cumulative update includes the latest servicing stack updates, to provide a single cumulative update payload to both WSUS and the Microsoft Update Catalog. If you use an endpoint management tool backed by WSUS, such as Configuration Manager, you'll only have to select and deploy the monthly cumulative update. The latest servicing stack updates will automatically be applied correctly. Release notes and file information for cumulative updates, including those related to the servicing stack, will be in a single KB article. The combined monthly cumulative update is available on Windows 10, version 2004 and later starting with KB4601382, released in February of 2021.