Microsoft has released the August 2026 preview update for Windows 11, delivered under the update name KB5120998. The patch targets both the newest 25H2 and the widely deployed 24H2 editions, and per Microsoft’s changelog it bundles a long list of improvements and fixes.
Preview updates like this one are the optional, in-between releases that land between the larger feature updates. They exist to test fixes and refinements before they roll out more broadly, so installing them is entirely up to you.
What KB5120998 actually is
KB5120998 is a monthly preview (also called a “C”) update. In Microsoft’s update cadence, the “D” update that follows it in September is typically the last preview of the year and often doubles as the annual feature update for the current cycle.
Because it’s a preview, this patch ships through the Optional Updates channel in Windows Update rather than being forced onto your PC. You’ll find it listed alongside other optional driver and quality patches, and you can install it or hold off without any penalty.
Coverage across 25H2 and 24H2
The update supports both Windows 11 25H2 and 24H2. 25H2 is the current major feature version, while 24H2 has been the standard for the past year and remains the most common build across the installed base.
Having a single preview patch cover both editions means Microsoft is consolidating its testing and distribution. In practice, that reduces the chance of version-specific regressions showing up separately, and it keeps the two editions closer in health over time.
If you’re still on an older build like 23H2, this patch won’t apply to you directly — you’d need to move to 24H2 or 25H2 first through the usual feature update path.
What’s in the changelog
According to the changelog, KB5120998 carries a long list of improvements and fixes. Preview updates typically touch on stability, app compatibility, and performance refinements, along with security-related fixes folded into the monthly patch.
Microsoft generally doesn’t spell out every individual fix in detail for preview releases, focusing instead on the categories of change. That means the exact list of addressed issues is best confirmed by checking the full changelog on Microsoft’s official support pages when you review the update.
One useful thing to note: preview updates are exactly where Microsoft catches problems before they reach the broader population. If you run into a new issue after installing one, it’s usually tracked and fixed in the following preview or the final “D” update.
What this means for you
For most users, KB5120998 is a low-risk, optional update. If your PC is running smoothly, there’s no urgent reason to rush it in. But if you’ve been experiencing a specific glitch, this preview may well include a fix for it.
Because it’s a preview rather than a mandatory quality update, you have full control over timing. Many power users wait for the first “D” update of the month — the one that follows the preview — to confirm stability before committing.
How to get it
To check for KB5120998, open Settings and go to Windows Update. Under the “Optional updates” section, you should see the August 2026 preview update listed. Select it and install, or choose to defer if you’d rather hold off.
Enterprise admins can deploy it through WSUS, Intune, or the Microsoft Update Catalog, where the KB5120998 catalog entry should now be available for both 25H2 and 24H2.
If you don’t see it yet, that’s normal — preview updates roll out in waves, and your machine may pick it up over the coming days as Microsoft widens distribution.
What this means for Windows 11’s update cycle
The August preview is part of the steady rhythm of Windows 11 patching that keeps 25H2 and 24H2 healthy through the summer. It sits ahead of the September “D” update, which historically carries the year’s feature additions for the current version cycle.
By consolidating preview support across both editions, Microsoft is signaling a push toward a more unified testing pipeline — one that reduces version drift and makes it easier to keep large fleets in a consistent state.
Source: Neowin
Over to you: Are you installing the August 2026 preview update now, or waiting for September’s final ‘D’ patch to confirm it’s stable?
