Microsoft announces first test build for Windows 11 26H1, aimed at 'specific silicon' — Rumor mill suggests first "H1" release in Windows 11's history might be reserved for upcoming Arm PCs

Windows 11 25H2, the operating system's latest major feature update, rolled out just last month. Just a few weeks ago, rumors of a "26H1" release started circulating, and now we have confirmation of its existence: Microsoft has just released the first build of Windows 11 26H1 — Preview Build 28000 — in the Canary channel of the Insider Preview program.

26H1 is in testing phases right now, and it will officially release early next year. This update is intended for a specific subset of users, with various reports suggesting that it is ARM. There are unsubstantiated rumors floating around, pointing to the upcoming Snapdragon X2 Elite and Nvidia N1X systems as candidates — since Qualcomm has scheduled the launch of its upcoming chips for early 2026, lining up with the 26H1 release.

Despite the implication, Microsoft doesn't explicitly mention any names in its announcement, so this is all speculation. "26H1 is not a feature update for version 25H2 and only includes platform changes to support specific silicon. There is no action required from customers," says the Redmont giant. That "specific silicon" phrasing is what has led many to believe it's referring to Snapdragon and Nvidia's upcoming chips.

So far, Windows 11 has maintained an yearly release cadence; Microsoft pushes a single feature update in the second half of each year, adding new functionality and improvements to the OS. Therefore, the releases are named "22H2," "23H2," "24H2," and so on. As such, 26H1 marks the first time the company has scheduled a major update for the start of the year, even if it's just to add support for specific ARM silicon.

"25H2 remains the primary place for new features. Windows 11 continues to have an annual feature update cadence, with releases in the second half of the calendar year."

Despite Microsoft confirming that 26H1 brings no new features, it's built on the new Bromine core — upgrading from the Germanium platform that powered Windows 11 25H2 and 24H2 — suggesting that once 26H1 is rolled into the eventual 26H2, it will be a substantial upgrade. Windows Insider also says that this Preview Build 28000 is the base RTM build for Windows 11 26H1, meaning Microsoft will lock this down and send it to OEMs (perhaps, Qualcomm and Nvidia) so they can start loading it onto their systems.

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