Microsoft Announces Public Preview of Hotpatching Support for Windows Server 2025

Microsoft has announced that hotpatching support is available in public preview for the Standard and Datacenter editions of Windows Server 2025. This feature allows organizations to apply OS security patches seamlessly, without the need for disruptive reboots.

Previously, hotpatching was only available for Windows Server 2022 Datacenter: Azure Edition and required running a virtual machine in Azure or on Azure Stack HCI. Typically, a system reboot is needed to apply patches and update system files. However, with hotpatching, administrators can update in-memory code on running processes to ensure continuous system availability without the need for reboots.

“The real change is how and where you get those security updates. Hotpatching will be available as an option through the power of Azure Arc. Azure Arc enables management and allows the Windows Server internal licensing service for Hotpatch to run so that Hotpatch updates are delivered to customers,” Microsoft explained.

What are the benefits of hotpatching?

With hotpatching, customers will only need to reboot their systems quarterly, reducing the number of reboots to just four times a year. Occasionally, a reboot might still be required when hotpatches are applied. These updates are smaller and more efficient, resulting in faster downloads, quicker installations, and lower disk space and CPU usage.

Microsoft noted that managing and coordinating patches can be complex and time-consuming. Hotpatching simplifies this process to make it easier to manage and control updates across servers. It also integrates with Azure Update Manager to offers a unified platform for managing updates, which is especially beneficial for hybrid environments.

Getting started with hotpatching in Windows Server 2025

To get started with hotpatching, IT admins must complete the enrollment process via the built-in Azure Arc agent, which comes pre-installed with the evaluation versions of Windows Server 2025 Datacenter and Standard editions. Once enrolled, administrators can enable the hotpatch preview feature to apply updates without requiring server reboots.

When Windows Server 2025 becomes generally available, organizations will be able to run it on-premises, in Azure, and other environments. Administrators will also be able to apply hotpatches to both physical servers and virtual machines (VMs). VMs running Windows Server 2025 can be hosted on various virtualization platforms, including Hyper-V and VMware.