Microsoft has released a new Windows Server vNext Preview Build 26404, which includes Desktop Experience and Server Core installation options for Datacenter and Standard editions, an annual channel for container hosting, and an Azure edition for VM evaluation. The branding remains Windows Server 2025, and the new build is automatically sent to Server Flighting subscribers. 

Announcing Windows Server vNext Preview Build 26404

Today we are pleased to release a new build of the next Windows Server Long-Term Servicing Channel (LTSC) Preview that contains both the Desktop Experience and Server Core installation options for Datacenter and Standard editions, Annual Channel for Container Host and Azure Edition (for VM evaluation only). Branding remains, Windows Server 2025, in this preview - when reporting issues please refer to Windows Server vNext preview.  If you signed up for Server Flighting, you should receive this new build automatically.

What's New

Windows Admin Center (WAC)Windows Server preview customers can download and install Windows Admin Center right from the Windows Server Desktop using the in-OS app that takes care of downloading and guides you through the installation process. 

Known Issues

Download Windows Server Insider Preview (microsoft.com)

Flighting: The label for this flight may incorrectly reference Windows 11. However, when selected, the package installed is the Windows Server update. Please ignore the label and proceed with installing your flight. This issue will be addressed in a future release.

Announcing Windows Server vNext Preview Build 26404 | Microsoft Community Hub