Credit: Microsoft

Since its release in the fall of 2021, Microsoft’s Windows 11 has received an “annual feature update” in the second half of every year. These feature updates sometimes include new Windows features and other changes that are too large to roll out in a typical monthly Windows Update, and users need to upgrade to new ones to keep getting security patches and other features. The currently supported versions are Windows 11 24H2 and 25H2, released in the fall of 2024 and 2025, respectively.

This week, Microsoft disrupted that update cadence by announcing more information on Windows 11 26H1, which is best described not as an update to Windows 11 but as another version of the operating system entirely. That’s because 26H1 is a “scoped” release intended exclusively for new PCs, starting with those based on Qualcomm’s recently announced Snapdragon X2 Elite chips.

Microsoft’s support page explains why this release is strange: It won’t be released broadly to other Windows 11 PCs, which should continue to use either 24H2 or 25H2. PCs running 24H2 or 25H2 will never be offered an update to version 26H1, though testers in the Windows Insider Program’s early access Canary channel are able to install it to other PCs if they want. (Build numbers for Windows 11 26H1 start with 28000, compared to 26100 for 24H2 and 26200 for 25H2.)

Users of PCs that ship with Windows 11 26H1 also won’t be able to upgrade to the next major release of Windows, which will presumably be released this fall as Windows 11 26H2. An update that will get the entire Windows ecosystem back on the same version number will be released, but the company isn’t saying when; assume it will happen before March 2028, which is the cutoff for security updates for the Home and Pro editions of Windows 11 26H1.

For most users, the behind-the-scenes distinction between these different Windows versions should be mostly invisible. Microsoft says that 26H1 “will continue receiving monthly updates for security, quality, and new features, the same as devices running Windows 11, versions 24H2 and 25H2.” And the company rolls so many new Windows features out through the Microsoft Store or through standard monthly updates that the underlying version of Windows matters less than it used to.

But for app developers, IT shops, and anyone else who needs to test things against multiple Windows versions at once, it does create an odd period of overlap where they’ll need to account for one version of Windows that runs just on these brand-new PCs, and one version of Windows that covers everybody else.

Special treatment for Arm PCs

Releasing a new version of Windows that just covers new Arm PCs is another signal of Microsoft’s commitment to Arm processors and the Arm version of Windows, after decades of near-exclusive focus on the x86 version of the OS that ran on Intel and AMD’s chips.

Microsoft offered multiple versions of both Windows 10 and Windows 11 in both x86 and Arm editions, but the 24H2 update was a major milestone for Arm PCs. It came with big under-the-hood changes to Windows’ compiler, kernel, and scheduler, and an optimized x86-to-Arm translation layer called Prism that enhanced the compatibility and performance of apps that hadn’t been built to run on Arm processors.

The 24H2 update also coincided with the release of the first-generation Qualcomm Snapdragon X-series processors, high-performance Arm chips developed by some of the same people behind Apple’s M-series chips for Macs. Many third-party developers have also finally released Arm-native versions of their Windows apps, which are faster and more responsive than translated x86 apps.

Microsoft’s confidence in the Arm version of Windows was so great that the new Surface PCs released in mid-2024 used Qualcomm’s processors exclusively, relegating Intel chips to offshoot versions for businesses with strict compatibility requirements. For years previously, Microsoft had treated the Intel- and AMD-based Surfaces as the “main” ones and the Arm-based Surface Pro X as the offshoot.

Since the 24H2 update, development on the Arm and the traditional x86 versions of Windows has happened at slightly different rates. Some features, particularly things like Recall and Click To Do that were only rolling out to Copilot+ PCs with fast built-in neural processing units (NPUs), have been available for the Arm versions of Windows for a few weeks or months before they hit the x86 versions. Windows 11 24H2 itself was also shipping on Arm PCs in stores several months before Microsoft began rolling the update out to the wider PC ecosystem.

We’ve asked Microsoft to elaborate on what the Windows 11 26H1 update includes and whether it contains any changes that will benefit the wider PC ecosystem somewhere down the line. We’ll update the article if we receive a response.