Microsoft Commences Testing of New Windows 11 Platform Changes in Dev Channel

Microsoft has commenced testing of new Windows 11 platform changes within its Insider Dev Channel. The company began releasing 26300 series builds, which advance the operating system's build number beyond current production versions. These builds are intended for underlying platform development, with an anticipated release later this year.

The 26300 series builds are intended for underlying platform development, with an anticipated release later this year.

Build Details

The 26300 series builds incorporate features and improvements consistent with the 26220 series builds, currently available in the Beta Channel. Microsoft confirmed that behind-the-scenes platform changes will be integrated into these builds, which may result in different known issues compared to prior versions.

Platform Codename and Release Schedule

The current in-market platform release of Windows 11 is codenamed Germanium, forming the basis for the 26300 series builds. Microsoft has not specified the exact nature of these platform changes.

Historically, Microsoft tested 26200 series builds that subsequently shipped as version 25H2. Following a similar pattern, the 26300 builds are expected to be released as version 26H2 in the fall for existing Windows 11 PCs.

In parallel, Microsoft plans to release version 26H1 this spring, exclusively for next-generation Arm devices. This 26H1 version is based on a newer Windows platform codenamed Bromine.

Consequently, the upcoming 26H2 version for existing PCs will utilize an older platform (Germanium) compared to the 26H1 release for Arm devices (Bromine).

Insider Participation

Insiders interested in evaluating these platform changes can access the 26300 series builds by enrolling in the Insider Dev Channel and initiating a check for updates via Windows Update. Currently, the Dev Channel and Beta Channel share similar feature sets and known issues.