“Windows 11 Insider Preview Build 25931 is now available on the Canary Channel, introducing new features such as Unicode Emoji 15 support and extended voice access. The update also includes changes to DC location and deprecates legacy technologies like WINS and Remote Mailslots.”

Windows 11 Insider Preview Build 25931: What’s New and Important
Windows Insiders, it’s time to explore the latest Windows 11 Insider Preview Build 25931. Released on the Canary Channel, this build introduces new features and significant improvements.
New Features from the Dev Channel
Build 25931 incorporates new features from the Dev Channel. These include Unicode Emoji 15 support and extended voice access, which is now available on more areas in Windows, including the Lock screen.
“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.”
Changes in DC Location Discovery
Another significant update is the discontinuation of NetBIOS/WINS/mailslot-based discovery by default for DC location. This change is due to the deprecation of Windows Internet Name Service (WINS) and Remote Mailslots, legacy technologies that are no longer secure in today’s environments.
Improvements to DC Locator Algorithm
To ease the transition, two improvements have been made to the DC locator algorithm. First, the use of NetBIOS/WINS/mailslot-based methods for DC-discovery is blocked by default. This can be reverted using a new Group Policy setting (BlockNetBIOSDiscovery).
Second, additional client-side logic has been added to aid in mapping short NetBIOS-style domain names to DNS domain names. This includes automatic download of additional information about child domains in trusting forests and manual configuration of DNS-to-NetBIOS-domain-name mappings.
“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).”
What’s Next?
As this build is hot off the press, limited documentation is available. However, keep an eye out for future blog posts detailing new features as they become available. Remember, reversion should be considered only as a temporary measure while more viable, longer-term solutions are explored.
From the Windows Blog