UPDATE 8/21: We are starting to roll out Cumulative Update Build 25931.1010 (KB5030120). This update does not include anything new and is designed to test our servicing pipeline for builds in the Canary Channel.
Hello Windows Insiders,
Today we are releasing Windows 11 Insider Preview Build 25931 to the Canary Channel. We are releasing ISOs for this build – they can be downloaded here.
REMINDER: As builds released to the Canary Channel are “hot off the presses,” we will offer limited documentation for builds flighted to the Canary Channel including documenting only the most significant and highly impactful known issues. Please note that we will not publish a blog post for every flight – only when new features are available in a build.
What’s new in Build 25931
New features from the Dev Channel
This build includes new features from the Dev Channel such as Unicode Emoji 15 support, voice access is available to use on more areas in Windows such as the Lock screen, and more.
DC location will no longer use NetBIOS\WINS\mailslot-based discovery by default
We have previously announced the deprecation of both Windows Internet Name Service (WINS) and Remote Mailslots (see this blog post here for information on Remote Mailslots). These deprecations are legacy technologies that are no longer secure in today’s environments. As part of these deprecations, DC location in your environment may be affected mainly because many legacy applications still specify short NetBIOS-style domain names when trying to locate a domain controller (DC). To help ease this transition with these deprecations, we are making two improvements to the DC locator algorithm in Windows.
First, we are blocking by default the use of NetBIOS\WINS\mailslot-based methods for DC-discovery. This behavior can be reverted with the use of a new Group Policy setting (BlockNetBIOSDiscovery). In addition to disabling the new BlockNetBIOSDiscovery policy, reversion to default behavior also requires enabling the EnableMailslots SMB configuration option. (You can query and set the EnableMailslots setting using the Get-SmbClientConfiguration and Set-SmbClientConfiguration PowerShell cmdlets.)
PLEASE NOTE: Reversion should be considered only as a temporary measure while more viable, longer-term solutions are explored.
Second, we have added additional client-side logic to aid in the mapping of short NetBIOS-style domain names to DNS domain names. This improvement consists of two parts:
Additional information is available here for DC locator changes.
Changes and Improvements
You can download the latest Windows Insider SDK at aka.ms/windowsinsidersdk.
SDK NuGet packages are now also flighting at NuGet Gallery | WindowsSDK which include:
These NuGet packages provide more granular access to the SDK and better integration in CI/CD pipelines.
SDK flights are now published for both the Canary and Dev Channels, so be sure to choose the right version for your Insider Channel.
Remember to use adaptive code when targeting new APIs to make sure your app runs on all customer machines, particularly when building against the Dev Channel SDK. Feature detection is recommended over OS version checks, as OS version checks are unreliable and will not work as expected in all cases.
About the Canary Channel
The Canary Channel is the place to preview platform changes that require longer-lead time before getting released to customers. Some examples of this include major changes to the Windows kernel, new APIs, etc. Builds that we release to the Canary Channel should not be seen as matched to any specific release of Windows and some of the changes we try out in the Canary Channel will never ship, and others could show up in future Windows releases when they’re ready.
The builds that will be flighted to the Canary Channel are “hot off the presses,” flighting very soon after they are built, which means very little validation and documentation will be done before they are offered to Insiders. These builds could include major issues that could result in not being able to use your PC correctly or even in some rare cases require you to reinstall Windows. We will offer limited documentation for the Canary Channel, but we will not publish a blog post for every flight – only when new features are available in a build.
Our Canary Channel won’t receive daily builds; however, we may ramp up releasing builds more frequently in the future.
The desktop watermark you see at the lower right corner of your desktop is normal for these pre-release builds.
Important Insider Links
Before you update your machine, visit the Announcing Windows 11 Insider Preview Build 25931 (Canary Channel) | Windows Insider Blog today to view full details on new features, general changes, improvements, known issues and much more!