Microsoft Azure has made significant September 2025 announcements with the added computational capability and availability of a massive regional deployment of its cloud computing platform. The latest version of Azure Local 2509 includes the new operating system versions, improved virtual machine management, and improved security baselines.
Azure Local 2509 is a dual-boot operating system
The Microsoft Learn documentation has two September releases with variations of solutions and operating system types. These releases are solution version 12.2509.1001.22 and OS version 26100.6584, solution version 11.2509.1001.21 and OS version 25398.1849. The new operating system now supports the 2504 release when providing Azure Local deployments, and 26100.5074 was released in the 2509 release as the operating system for all deployments, which can be downloaded through the Azure portal.
It also should be compatible with the OS equivalent of 26100.5074 or the Windows server equivalent of 2025. In case there is no compatible driver to use, the image number 2503 can be used. Current deployments in Azure Local still have version 25398.1840 of the OS. OS is preinstalled if you have purchased the hardware of the Integrated System or Premier solution via Azure Local Catalog from one of the Microsoft hardware partners.
downloads a compatible operating system (OS) image and driver with OS version 26100.5074 or Windows Server version 2025. Contact the Original Equipment Manufacturer (OEM) for information on the image of the OS that is supported for 12.2509 and of a compatible driver for the OS version 26100.5074 version or Windows Server 2025 version.
Better performance of the virtual machine, easy control of storage
With this release, you can view all the dependent resources on a storage path before it is deleted. Azure portal also allows you to remove the storage path along with all its dependent resources under one block operation, and make it easier to clean up neatly and make it feel more native. Now you can live update (VM is running) the memory of a VM. An exception only occurs when the guest operating system does not support live-memory update, which may require restarting the guest operating system.
There is a huge change in the version number of the .NET Framework.
This build version is .NET v8.0.20, both ASP.NET Core and .NET Runtime, which is drastically better than previous versions. With this release, you can choose to upgrade to solution version 12.25xx (having running OS 26100.xxxx) to solution version 11.25xx (having running OS 25398.xxx). The default size of the OS disk of AKS VM is increased from 100 GB to 200 GB to provide flexibility for sizing of the containerized workloads.
This download of Windows VHD images is set to begin by default. Azure Local and Local identity deployment also has external and internal zone names with local DNS servers. Documentation changes include exciting changes with new articles or articles with massive changes. Upgrade and update document changes include adding new articles and major revisions in existing articles, and the latest update to perform Opt-in update to Azure Local solution version 12.25x is released.
Improvements are made to the security of the platforms
As part of 2506, Vulnerability Manager performs a fixed firewall security baseline release comprising 407 rules assessed (an improvement of 25 percent over the 324 rules assessed in the previous release). The more significant improvements are over 90 percent CIS Azure Compute windows and Defense Information System Agency (DISA) security technical implementation guide (STIG) compliance.
Further, A change to Azure in September 2025 continues to make significant advancements in the infrastructure of cloud computing and provides improved performance, security, and management across the platform. The mixed operating system model supports and enables organisations to benefit from state-of-the-art components. Combined with the virtual machines and security foundations, and disaster recovery features, these end-to-end enhancements make Azure Local a strong contender in the current enterprise computing needs and hybrid cloud implementations.