Back in 2022, Microsoft released a new variation of Windows 11 named Validation OS. While this operating system is not meant for the general user, it, as the name suggests, is designed to be utilized in the validation, diagnosis and repair of new hardware, ensuring software compatibility, and for troubleshooting various issues. It is based on command line interface (CLI). Here's how Microsoft describes it: Microsoft Validation OS is a lightweight, fast, and customizable Windows 11-based operating system that you can use on the factory floor to diagnose, mitigate and repair hardware defects during Windows device manufacturing. Validation OS boots into a Command Line environment to increase reliability on the factory floor and supports running Win32 apps, smoothing the transition from early hardware bring-up to retail OS and apps development. Over time, Microsoft has been releasing updates for it, which have included support for Windows 11 24H2. That was back in July of 2024. However, back then, Microsoft did not publish any changelog or release notes for the Validation OS updates. However, towards the end of last year, the company started releasing monthly updates for it and has also been publishing corresponding release notes. The latest update was released earlier today with upgrades and enhancements for .NET and WPF (Windows Presentation Framework) UI framework. It also has improvements related to USB booting for Windows PE (preinstallation environment) Ramdisk mode. Microsoft writes (spotted by DeskModder): The following release notes identify the new features, open issues, and resolved issues for the 2504 release of the Microsoft Validation OS. ... This article applies to the Validation OS 2504 release, corresponding to the ISOs with the prefix "26100.3916.250422-2254". What's new Windows Hardware Lab Kit on Validation OS enhancements: Added Surface Dock specific drivers to the Microsoft-WinVOS-DriversPack-A package Added basic support to run some WPF applications along with sufficient support to run .NET (former ".NET core") and WPF on .NET (former "WPF on .NET core") via the Microsoft-WinVOS-WPF-Support optional package (under the Extras CAB directory) Migrated to the latest most secure and performant .NET implementation Split Chinese, Japanese, and Korean TrueType support from Microsoft-WinVOS-Fonts into Microsoft-WinVOS-CJKFonts Added support to ‘DISM.exe /Image: /Set-ScratchSpace’ on Validation OS when booting from USB to configure RAM-DISK size via the Microsoft-WinVOS-Provisioning package Issues Fixed Enhancements and bug fixes Known Issues When including both Microsoft-OneCore-SerialConsole-Package and Microsoft-WinVOS-Bluetooth-Package on certain ARM64 systems, the machine will become unstable and can crash. In case you are wondering, the previous two releases added support for OOBE (out of box experience) and Inbox drivers, like that of the Ethernet. The changelogs are given below: The following release notes identify the new features, open issues, and resolved issues for the 2025.02 release of the Microsoft Validation OS. .. This article applies to the Validation OS 2025.02 release, corresponding to the ISOs with the prefix "26100.3323.250220-1537". What's new Added a the “Inbox Drivers” feature package that adds a limited subset of inbox drivers, including some ASIX ethernet adapters. When including the Out of Box Experience (OOBE.pkg) in an image targeted FOR USB boot, GenImage will automatically filter out Microsoft-WinVOS-Setup-Package from the composition (this package is unsupported in durin USB boot). Includes an experimental script to convert a generated Validation OS WIM file to a custom sized VHDX: GenImage\CustomVHDX.cmd Issues Fixed Fixed issue where kernel mode crash dumps were only created if the Power feature was included in the composition. Now, there are no option package requirements for kernel mode crash dump creations. Known Issues When including both Microsoft-OneCore-SerialConsole-Package and Microsoft-WinVOS-Bluetooth-Package on certain ARM64 systems, the machine will become unstable and can crash. The Microsoft-WinVOS-Setup-Package is located in both the common package location and under OOBE (this is fixed in the upcoming March 2025 release) Adding the Out of Box Experience (OOBE.pkg) package to arm64 devices will result in an infinite reboot cycle (this will be fixed in the upcoming March 2025 release) Image generation is not possible if the input (base) WIM/VHDX is compressed. This is a limitation of dism.exe and considered by design. [....] The following release notes identify the new features, open issues, and resolved issues for the 2503 release of the Microsoft Validation OS. .. This article applies to the Validation OS 2503 release, corresponding to the ISOs with the prefix "26100.3624.250321-2034". What's new Windows Hardware Lab Kit on Validation OS enhancements: Added built-in support for Out of Box Experience (OOBE.pkg) Added support for certain hardware devices via the Microsoft-WinVOS-DriversPack-A-Package VHDX images are now bootable in Hyper-V with no additional updates Added takeown.exe and driverquery.exe utilities to the Applications and Application Support (apps.pkg) feature package. Added Validation OS specific DirectML samples to Github:Validation-OS/Samples/DirectML Issues Fixed The Microsoft-WinVOS-Setup-Package.cab file is now only located in the OOBE package location Adding the Out of Box Experience (OOBE.pkg) package to arm64 devices will not result in an infinite reboot cycle anymore Fixed ApiSet Schema for Microsoft-WinVOS-Connectivity-Devices Known Issues When including both Microsoft-OneCore-SerialConsole-Package and Microsoft-WinVOS-Bluetooth-Package on certain ARM64 systems, the machine will become unstable and can crash. To download the latest Validation OS release, head over to this page on Microsoft's official website.