Windows Server Hotpatching: Hope or Hype?

23rd May 2025

Microsoft recently announced they are making hotpatching available for Windows Server 2025 systems on July 1, 2025. Articles posted, rumors flew, and speculation ensued.

So, what’s the big deal?

At a high level, hotpatching is the ability to update a server, often for security reasons, without having to reboot it. The benefits are especially impactful for environments requiring high availability with the promises of more uptime/less downtime and operational efficiency.

Unfortunately, Microsoft is delivering late. Linux has had hotpatching since 2015. Microsoft employed hotpatching for Windows Server in Azure in 2022 but waited until 2024 to offer a preview for customers. It took months for Microsoft to build hotpatching into the latest release of Windows Server in November 2024.

All that wasted time! Right?

Well, Microsoft absolutely needed more time to devise the on-premises hotpatching process. It also may be that Microsoft wanted time to develop:

  • A monetization scheme.
  • Establish a licensing method.
  • Build a seller playbook for Microsoft sellers to create more Azure “value” and drive new revenue.

The impact and personnel ramifications of these requirements, along with Microsoft’s intentions, will take time to fully understand.

Requirements and Impact

Microsoft’s requirements are clearly defined, though some details are harder to locate than others—and new requirements may continue to emerge. For each known requirement, there are impacts to consider for in-place hardware, constant connectivity to Microsoft, fees and future upgrades.

Hardware

Supporting Virtualization-Based Security (VBS) and Unified Extensible Firmware Interface (UEFI) with Secure Boot isn’t optional. While these capabilities have been widely available since 2015, the impact is that incorrect configuration could cause failure. While relatively easy to overcome through testing, process documentation for upgrades and new deployments should include special notation.

Azure Arc

Built as a “governance and management platform” across on-premises and cloud environments, Microsoft also leverages the Azure Arc connection to deliver licensing-related services to “Azure Arc-enabled servers” including:

  • Extended Security Updates (ESU) for older systems.
  • Security offerings such as Defender for Servers and Microsoft Sentinel.
  • Windows Server and SQL Server pay-as-you-go (PAYG) licensing.

Azure Arc isn’t difficult to establish, and there isn’t a “platform” cost. The impact is that Azure Arc creates a constant connection to enabled servers. Buying products can be confusing when determining the best licensing approach for offerings also available in the traditional Enterprise Agreement (EA) and other volume license programs.

Per-core fees

Microsoft plans to charge $1.50/month per physical core, impacting costs for on-premises server licensing. Though not published, Microsoft is also likely to make Software Assurance (“SA”) a requirement. Hotpatching costs, compared to SA costs, will vary wildly:

  • Standard Edition: costs for standalone servers may increase 100% or more, while costs for servers hosting instance-based VM licensing may increase 40-50%.
  • Datacenter Edition: servers hosting multiple VMs, licensed with Datacenter edition, will likely incur a ~15% cost increase.

Customers aiming for early adoption or upgrading to new platforms should consider budgeting for hotpatching fees in 2026, although it’s more likely these costs will arise in 2027, when Windows Server 2025 becomes mainstream.

Windows Server 2025 Standard or Datacenter

Few large organizations will have Windows Server 2025 deployed in volume by summer of 2025. Historically, organizations have waited 6-18 months before considering rollouts beyond testing and development. The impact is that it will take months or years for broad adoption, requiring upgrade planning and separate processes when hotpatching is employed, complicating and confusing the hotpatching processes organizations must employ.

Personnel Ramifications

While Information Technology (IT) teams will be most impacted, others in the organization must deal with the potential onslaught of sales and marketing messages coming from Microsoft.

Internal IT

IT personnel may need new and more complex approaches to patching. Unlike true hotpatching, in which a system may go years without a reboot, Windows Server 2025 hotpatching will require organizations to reboot systems at least every quarter with additional reboots for emergencies such as zero-day exploits. IT organizations will need to establish separate patching and confirmation processes for systems using hotpatching, including quarterly reboots, non-reboot months and emergency updates.

Additionally, IT must maintain existing processes for monthly and exploit-driven patches since Windows Server 2022 and prior systems do not include a hotpatching option (for now). IT personnel will face managing different processes until:

  • All systems upgraded to 2025
  • Microsoft offers hotpatching for older versions.
  • Other operating systems are employed.
  • Systems move to the cloud.

Application owners

Upgrades. Migrating to an updated version or evaluating alternatives requires cost modeling for hardware, licensing, personnel and consultants. New applications are highly likely to include Artificial Intelligence (AI) and will require thorough analysis of data governance within company policy. Developing, approving, and executing budgets and project plans take time and effort, likely stretching into 2026. Nimble organizations, including those delivering hosted solutions, may be able to upgrade more quickly. Larger organizations are likely to take years.

Non-IT Teams

Management is likely to see more sales pressure to upgrade, connect and “drive value” while those involved with procurement may be stuck with the financial analysis, negotiations and budget planning. Moreover, Microsoft sellers are likely to leverage the hotpatching conversation to drive other solutions – especially Azure.

Microsoft Intentions

Microsoft built hotpatching into Azure-based systems to ease their own burden of managing delivery. All that code… sitting there… adding value… internally. Could hotpatching development be recouped through customer fees or be used as leverage in other ways?

Entrench Azure Arc

Establishing a continual connection creates opportunity. Marketing can they say that customers connected to Azure Arc are “Azure customers” even if they’re fully running in AWS and only using Azure Arc for ESU. Sellers can offer PAYG subscriptions vs. buying “legacy” licenses, which may make sense in select scenarios (e.g., a retired application used once per month for reporting) but doesn’t in others.

Will Microsoft change their terms and conditions and leverage the connection in audits?

Monetize Azure investments

“Windows Server 2022 in Azure” included a hotpatching option. Microsoft could have added hotpatching as a feature, or technology update, to the latest Windows Server release first and then later for prior versions.

I recently heard a radio segment marking the anniversary of Windows 3.0’s release, highlighting features like the inclusion of a basic “Calculator.” Microsoft sees an opportunity to drive revenue, create leverage or both. They already wrote off code/sunk cost and have benefitted internally for years.

More subscriptions, more margin

Boiling the frog. Well… don’t boil a frog, but Microsoft is doing that figuratively with licensing. They introduce, bit by bit, the ability to buy services, subscriptions and licensing through their own channel. Not only do they have control over price and delivery, but they’re also eliminating partner margin and complexity of buying through a channel.

As more subscriptions are added through Azure Arc, customers will increasingly adopt the operational expense model and gradually adjust to this new way of consuming services. Yet using legacy SA licenses in Azure, compared to the Azure subscription cost, if often 50% less in licensing costs.

Equalize Azure and on-premises costs

  • ESU: could Microsoft reduce the duration of the support lifecycle to drive newer version adoption or secure fees for older ones?
  • Hotpatching: will Microsoft offer this for older versions to expand the footprint and usage, eventually building it into all Windows Server versions and using it as the reason for a price increase?
  • Product Scope: Windows Server, SQL Server, Defender, Sentinel and more can be purchased for on-premises systems through Azure Arc. But is it cost-effective? Do traditional contracts offer these at a better price?
  • Viable Alternatives: If you want to use a different cloud provider – AWS, GCP, OCI, or even third-party hosting – you’ll have to configure and pay for things that are “just included” in Azure.

And finally…

Is this all hope or hype? Hotpatching is an interesting technology, especially for environments requiring high availability. Microsoft deserves credit for finally joining the conversation. In my opinion, Windows Server hotpatching is mostly hype mixed with some hope – in the form of sellers and Microsoft aiming for more revenue.

Curtis Browne, Microsoft Practice Lead at Remend