See what's coming in Windows Server 2025

Changes to Windows Server licensing

One big adjustment for organizations that rely on Windows Server is Microsoft's plan to introduce a subscription-based, pay-as-you-go licensing model. Contrary to some rumors, Microsoft is not forcing all Windows Server customers into the subscription plan.

Microsoft plans to keep the perpetual license model, which provides five years of mainstream support followed by five years of extended support. With Windows Server 2025, Microsoft will offer a subscription model for organizations that need flexibility.

For example, if an organization hosts an e-commerce application that sees a major demand spike around the holidays, then it could use Windows Server 2025 with a pay-as-you-go license to roll out temporary servers to handle this period of peak activity. This approach gives the business a more affordable option to cope with these seasonal surges without making a major investment for resources needed for part of the year.

Enterprises that wish to use the new pay-as-you-go licensing for Windows Server 2025 must use Azure Arc -- a cross-platform management tool for enterprise workloads -- and the related charges will be billed through Azure.

Hotpatching coming to all Windows Server 2025 editions

The portion of the Windows Server 2025 announcement that received the most notice at the 2023 Ignite conference was related to hotpatching, which lets the admin apply security updates without a reboot. Typically, a reboot is required to complete the patch process to allow changes to system files.

Hotpatching is currently available in Windows Server 2022 Datacenter: Azure Edition, but Microsoft plans to add this feature to the Standard and Datacenter editions of Windows Server 2025.

Early reports indicate Microsoft will charge customers an add-on subscription to use hotpatching, which requires Azure Arc and Software Assurance.

The amount of online enthusiasm around Windows Server hotpatching indicates many enterprises will accept the extra cost for this convenience. With this capability, many organizations may rethink their patch management strategy. For example, they may choose to apply patches more quickly without waiting for off-peak hours.

Storage improvements in Windows Server 2025

Microsoft plans to bring several storage-related improvements in Windows Server 2025. One of the bigger developments is servers that use non-volatile memory express (NVMe) storage should see a huge performance improvement. Microsoft claimed customers will see a 70% increase in IOPS when using Windows Server 2025 with NVMe storage.

Microsoft said Windows Server 2025 will support NVMe over Fabrics, the interface specification and storage protocol that is gaining traction as the connectivity method of choice in storage area networks due to its fast data transfer speeds.

Other storage-related improvements in the new server OS include native deduplication for Resilient File System storage and Server Message Block over QUIC, a storage protocol that uses Transport Layer Security 1.3 to encrypt SMB traffic. SMB over QUIC is already available in Windows Server 2022 Datacenter: Azure Edition. However, with Windows Server 2025, Microsoft will include it with the Standard, Datacenter and Azure editions.

Changes to Hyper-V

Windows Server 2025 will see at least three significant changes to its Hyper-V virtualization technology, although Microsoft has hinted there may be more capabilities in development.

First, generation 2 VMs will replace generation 1 VMs as the default choice when creating new VMs. Microsoft built generation 1 VMs for backward compatibility with older OSes, such as Windows Server 2008 and Windows 7. Generation 1 VMs also support 32-bit Windows versions and some non-Windows OSes.

Although generation 1 VMs still have their place, the Windows OSes that require them have no Microsoft support. The decision to make generation 2 VMs the default option makes sense, considering Microsoft introduced generation 2 VMs with Windows Server 2012 R2.

Another change coming to Hyper-V in Windows Server 2025 is dynamic processor compatibility. With current versions of Windows Server, a live migration of VMs between two Hyper-V hosts requires using servers with identical CPUs or enabling processor compatibility mode, which makes CPUs function at the most basic level. With the dynamic compatibility feature in Windows Server 2025, Hyper-V will compare CPUs across hosts and use CPU functionality supported by both processors, even if those processors are not identical.

Lastly, Microsoft plans to improve GPU partitioning (GPU-P) support, which gives the user a way to employ the processing power of the server's GPU and share it among multiple VMs. This new GPU partitioning capability also adds live migrations between servers using GPU-P and GPU pooling to combine several GPUs for failover clustering.

Support for Microsoft 365 Apps

Despite the popularity of Microsoft 365, not every organization can or wants to use this cloud collaboration platform. Some reasons include compliance or cost concerns. Some businesses need a way to use an on-premises Windows Server system, such as Microsoft 365 Apps, to run via Remote Desktop Services so users can connect remotely.

Not all that long ago, Microsoft announced Microsoft 365 Apps would only be supported through October 2026, which is when mainstream support for Windows Server 2022 ends. However, Microsoft revised this policy and will support Microsoft 365 Apps on Windows Server 2025 until the end of the five-year mainstream period.

Brien Posey is a 15-time Microsoft MVP with two decades of IT experience. He has served as a lead network engineer for the U.S. Department of Defense and as a network administrator for some of the largest insurance companies in America.