Microsoft today released a preview version of Win11 Build 25951 for Canary channel users. At the same time, it also released a new preview version of Windows Server Build 25951 for Long-Term Servicing Channel (LTSC) channel users today.
Users in need can go to the Windows Server Insider website to download the ISO or VHDX image for installation. As before, the new preview integrates the Win11 desktop experience and is available in Datacenter, Standard, and Azure editions (only virtual machine installations are supported).

Microsoft has updated a dedicated blog post for Windows Server, but the updated content is the same as Build 25941. The following content attached here:
Update Content
Enable Servers onboarding experience for Azure Arc
After users upgrade to this preview, they will find the new Azure Arc icon in the system tray (lower right corner of the taskbar).
After users click it, they can start the Azure Arc installation wizard to install and configure the (free) Azure Connected Machine Agent.
After Azure Arc is enabled on the server, look for status information in the system tray icon.
Server Datacenter opens new version of Terminal application:
Use the Terminal command line utility on Windows Server for a test run! Search for “Terminal” on the latest Server Datacenter Insider version and launch the application.
Provide Storage Replica Enhanced Log
Enhanced logging improves the performance of block replication by removing the file system abstraction and its performance cost from the storage replica logging implementation.
Known issues:
If you are planning a validated upgrade from Windows Server 2019, you may experience intermittent upgrade failures if you upgrade to this version, and we do not recommend it.
There is an issue with this release where archiving event logs using the “wevetutil al” command causes the Windows Event Log service to crash and the archive operation to fail. The service must be restarted by executing “Start-Service EventLog” at an administrative command line prompt.
We do not recommend installing this version if you have the Secure Boot/DRTM code path enabled.
Server’s branding has not been updated and is still Windows Server 2022 in preview. Additionally, Microsoft is calling these versions Windows Server vNext, rather than Windows Server 2022, which is already available.
Available downloads:
Windows Server LTSC preview in ISO format in 18 languages and in VHDX format only in English.
Windows Server Datacenter Azure preview in ISO and VHDX formats, English only.
Microsoft Server Languages and Optional Features Preview
The key is only valid for preview builds:
Server standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH
Data center: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67
Azure version does not accept keys
Microsoft also notes that this preview will expire on September 15, 2023. Netizens who need it can click here to download the image, and the update log address is: here.