Windows Server vNext build 25921 is released to Windows Insiders with some new features

Microsoft has released a new build of the Windows Server Long-Term Servicing Channel (LTSC) Preview. Today's build 25921 is now available to download as an ISO from the Windows Server Insider website along with a VHDX. It contains both the (Windows 11) Desktop Experience as well as a Server Core installation option for Datacenter and the Standard edition. There's also an Azure Edition, but it's only available via virtual machines.

There is a dedicated blog post for this new release which does have a changelog for the first time in a long time for a Windows Server Insider launch:

What's New

Server Datacenter Insiders! Take Terminal command line utility on Windows Server for a test run! Search for "Terminal" on the latest Server Datacenter Insider build and launch the application.

Storage Replica Enhanced Log is now available in the latest Windows Server Insider build. Enhanced Log provides improved performance for block replication by removing file system abstractions – and their performance costs – from the Storage Replica log implementation. More info, and deployment instruction, is available on Learn: link.

There are also a few known issues with this release:

If you are validating upgrades from Windows Server 2019, we do not recommend that you use this build as intermittent upgrade failures have been identified for this build.

This build has an issue where archiving eventlogs with "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" from an administrative command line prompt.

If you have Secure Launch/DRTM code path enabled, we do not recommend that you install this build.

The Windows Server Preview currently is on the same build number as the Windows 11 Insider Canary channel, which might indicate we won't see a new Server version until next year when Windows 12 is expected to be released.

Here's some more important info on this release:

Available Downloads

Downloads to certain countries may not be available. See Microsoft suspends new sales in Russia - Microsoft On the Issues

Windows Server Long-Term Servicing Channel Preview in ISO format in 18 languages, and in VHDX format in English only.

Windows Server Datacenter Azure Edition Preview in ISO and VHDX format, English only.

Microsoft Server Languages and Optional Features Preview

Keys: Keys are valid for preview builds only

Server Standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH

Datacenter: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67

Azure Edition does not accept a key

Symbols: available on the public symbol server – see Using the Microsoft Symbol Server.

Expiration: This Windows Server Preview will expire September 15, 2023.