Windows updates bring many new features, performance improvements, bug fixes, security upgrades, and more to Microsoft's magnum opus of an operating system. However, you might see terminologies like critical update, cumulative update, security update, patches, or hotfixes and wonder what they all mean.

Well, we're here to help you learn the important terms that everyone needs to know, so you know just what you're downloading and why. Here's what these important Windows update terms mean.

Infographic on The Main Windows Update Terms, Explained

1. What Is a "Patch?"

PHP code

A patch is simply a piece of code that Microsoft has added to Windows to fix errors that affect performance or security. Sometimes, a patch will also bring new functionality.

2. What Is a "Hotfix?"

A hotfix is a patch that aims to quickly resolve specific issues that users have reported – usually after they have downloaded an update. It is released without going through the full patching process, which is why they're deemed quick fixes. However, that doesn't make them any less important.

3. What Is a "Critical Update" in Windows Update?

When Microsoft releases a critical update for Windows, it has patched a specific problem that was preventing the operating system from running properly. The problem is usually something that a significant number of users are experiencing, such as errors or unexpected behavior, but it's not security-related. Microsoft recommends that you install a critical update the moment it's available.

4. How About a "Feature Update?"

Windows 10 feature update 21h2 ready to install

A feature update is basically the latest version of the Windows operating system you're currently using. It brings with it new functionality and tightens up security loopholes, on top of adding all the fixes and improvements from previous versions.

Microsoft used to release two feature updates a year (in Spring and Fall) during the time of Windows 10. It would then support that version of Windows for the next 18 months, while support for the previous version would end.

With Windows 11, Microsoft now releases feature updates annually in the second half of the year. Home and Pro editions of that Windows version will be supported for 24 months, while the Enterprise and Education versions get 36 months of support. Once Microsoft stops supporting a particular version of Windows, you will need to update to the currently supported one to continue receiving updates.

5. What Is a "Cumulative Update?"

A cumulative or quality update combines several patches, hotfixes, and critical and non-critical updates meant to address performance and security issues on Windows. This update also bundles previous updates to that point, allowing you to apply several changes that truly bring your current version of Windows up to date all at once.

6. What Is a "Service Pack?"

A service pack is an easily-deployable cumulative update that delivers patches, hotfixes, and updates (both critical and non-critical). Microsoft may also include new design and functionality changes that users request through various feedback channels.

7. What Is a Windows "Security Update?"

Microsoft releases a security update when it has patched a major security vulnerability reported by major corporations. Microsoft will label this update as either critical, important, moderate, or low, depending on the severity. Not downloading a security update increases the risk that different types of cybercriminals will attack your PC.

8. What Are "Feature Packs?"

A Feature Pack (FP) is essentially an optional cumulative update containing design and feature changes, improvements, and even fixes that are tied to a specific area of the operating system or its functionality.

9. What Constitutes an "Update Rollup?"

An update rollup is a cumulative update meant to fix or update a specific part of Windows. For example, Microsoft can release an update rollup to patch Windows security vulnerabilities. It can even target an operating system component, such as Windows Media Services or SharePoint through an update rollup.

10. What About "Upgrades"?

Person using Windows 11 laptop

An upgrade means updating a major version of Windows to the latest one – be sure not to confuse it with a feature update, though. An example of an upgrade would be moving from Windows 10 to 11, and a feature update would be updating from Windows 11 21H2 to 21H2.

On that note, if you are on Windows 10 and thinking of upgrading, please read our guide on the things you should do before installing Windows 11.

Now You Know the Most Important Windows Update Lingo

This list of Windows update terminology only scratches the surface – we can't possibly cover them all in a single list. However, you'll encounter these terms mentioned above in many update scenarios, and it helps to know what they are, especially if you're new to Windows.