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Windows Server Preview Build 26040 adds Server Flighting; Windows Server 2025 branding

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Microsoft has released the first Windows Server preview build of 2024 for members of the Windows Server Insider Program. The build number is 26040, which is the same as the new Canary Channel preview build for Windows 11.

This new version is also the first to support the Server Flighting feature for updates, and it has been branded as Windows Server 2025. Here is the changelog:

Announcing Windows Server Preview Build 26040

Hello Windows Server Insiders!

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 has been updated for the upcoming release, Windows Server 2025 in this preview - when reporting issues please refer to Windows Server 2025 preview.

What's New

Windows Server Flighting is here!!

[NEW] If you signed up for Server Flighting, you should receive this new build automatically later today (Friday, January 26, 2024).

Join Server Flighting

To set up flighting on Server (build 26010 or later), just navigate to Settings > Windows Update > Windows Insider Program to opt in your device. Flighting will only be available for the Canary Channel and flights for Server begin with build 26040. Our intention is to flight the same builds as client (desktop) for Server flights but the schedule in which we release Server flights might differ slightly (for example – Server releases bi-weekly). Flighting for Server applies to the Desktop Experience only.

windows server flighting

The following new features are specific to Windows Server with Desktop Experience only. Some of these will require running the OS on physical systems AND having the right drivers on hand.

Additions to Accounts: Email & Accounts is now consistent with Windows 11. Please note, domain join will still be necessary for most scenarios.

  • Call to action: Please try adding Microsoft accounts and/or work accounts along with relevant apps that take advantage of this.

Increased coverage for Bluetooth devices. Many of you want to use BT to connect mice, keyboards, and audio devices at the Edge. Please try out your favorite keyboard, mouse, headphones, or other BT peripheral!

  • Wi-Fi present by default. Many of you want to connect servers to Wi-Fi networks at the Edge. While Wireless LAN service has been present in Windows Server, it was disabled by default. Wi-Fi support is now currently enabled by default for Edge scenarios. You will need the appropriate hardware and drivers handy. Please verify that your wireless devices work properly. When hardware and the correct drivers are present, see the corresponding Settings and Taskbar experiences. Let us know what you think!

[NEW] SMB over QUIC alternative server port

Starting with Insider Build 26040, the SMB server now supports listening on an alternative network port for SMB over QUIC instead of hardcoded default. Previously, SMB over QUIC only supported QUIC(UDP)/443, but now you can choose any unused port from 1-65535. Windows Server Insider does not support configuring alternative SMB server TCP or RDMA ports at this time; if you organization has scenarios where it would be useful to configure those ports, message Ned Pyle, SMB PM, at About Ned Pyle - Microsoft Community Hub.

You can specify an alternative SMB over QUIC server port using the New-SmbServerAlternativePort PowerShell cmdlet.

For more information on using this option, review https://aka.ms/SMBAlternativePorts.

Known Issues

Setup: Some users may experience overlapping rectangle voids following mouse clicks during "OOBE" setup. This is a graphics rendering issue and will not prevent setup from completing. This issue will be addressed in a future release.

WinPE - Powershell Scripts: Applying the WinPE-Powershell optional component does not properly install Powershell in WinPE. As a result, Powershell cmdlets will fail. Customers who are dependent on Powershell in WinPE should not use this build.

The new Feedback Hub app is not functioning properly in this release due to known issues. These will be addressed in a future release. Please continue to submit feedback as described in the "We value your feedback!" section below.

If you are validating upgrades from Windows Server 2019 or 2022, 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.

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, 2024.

You can still download the new Windows Server preview from Microsoft's site. You can check out the full blog post here.

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