Windows Server 2016 End of Support (January 12, 2027): What Your Business Should Do Now

If your business still runs Windows Server 2016, the clock is ticking. Microsoft’s extended support for Windows Server 2016 ends on January 12, 2027. After that date, Microsoft stops releasing regular security updates for it.

This guide explains what end of support means, how much time you have, which version to move to (Windows Server 2025, 2022, or 2019), and the licensing basics you need to get right, including Client Access Licenses (CALs).

What “end of support” means for Windows Server 2016

Windows Server 2016 follows Microsoft’s Fixed Lifecycle Policy. That means it had two support phases:

• Mainstream support ended on January 11, 2022 (the last day before Microsoft’s January 12, 2022 cutoff). That was the end of new features and non-security fixes.
• Extended support ends on January 12, 2027. Until then, Microsoft still ships security updates.

After January 12, 2027, Windows Server 2016 will keep running. It won’t shut off or stop booting. But it will stop getting the monthly security patches that protect it from newly found vulnerabilities, unless you enroll in Microsoft’s paid Extended Security Updates program (more on that below).

This applies to all Windows Server 2016 editions: Standard, Datacenter, Essentials, and MultiPoint Premium. Containers released with Windows Server 2016 follow the same dates.

Windows Server support dates at a glance

Here’s how Windows Server 2016 compares with the versions you can move to. All dates come from Microsoft’s official lifecycle pages.

The takeaway: Windows Server 2025 gives you the longest runway, with security updates into late 2034. Windows Server 2019 already has just over two years of support left.

The risks of running an unsupported server

Running Windows Server 2016 after January 12, 2027 without Extended Security Updates means:

• No new security patches. Vulnerabilities found after that date stay open on your server.
• Compliance problems. Many security frameworks, cyber insurance policies, and industry rules expect systems to be on supported, patched software. An unsupported server can be a finding in an audit.
• Software and vendor support gaps. Application vendors often drop support for operating systems that Microsoft no longer supports. Your line-of-business software, backup agents, or security tools may stop certifying Windows Server 2016.
• No Microsoft technical help. Once a product leaves support, Microsoft no longer offers standard support for it.

Servers often sit at the center of your network, running file shares, Active Directory, line-of-business apps, and remote access. That makes an unpatched server a bigger risk than one unpatched PC.

Your options before January 12, 2027

You have three realistic paths.

Option 1: Upgrade to a newer Windows Server version (recommended for most)

For most small and mid-sized businesses, the simplest long-term fix is to move to a supported version of Windows Server. Microsoft supports an in-place upgrade from Windows Server 2016 directly to Windows Server 2019, 2022, or 2025 using installation media. Starting with Windows Server 2025, non-clustered servers can upgrade up to four versions at a time, so 2016 to 2025 is a single step.

Option 2: Buy Extended Security Updates (a short-term bridge)

Microsoft announced Extended Security Updates (ESUs) for Windows Server 2016 in February 2026. Key facts:

• ESUs provide Critical and Important security updates for up to three years, through 2030.
• They’re delivered through Azure Arc. You could configure them in the Azure portal starting August 3, 2026, and billing begins January 13, 2027.
• They cover Standard and Datacenter editions.
• To buy them, you need Software Assurance through a Microsoft volume licensing program (such as an Enterprise Agreement or Open Value), or your servers must be licensed through SPLA or a Server Subscription.
• ESUs include no new features, no non-security fixes, and no technical support.

Microsoft itself calls ESUs a “last resort” and a temporary bridge, not a long-term plan. If you bought Windows Server 2016 as a one-time license without Software Assurance, ESUs likely aren’t available to you, which makes upgrading the practical choice.

Option 3: Move workloads to the cloud

Some businesses use end of support as the moment to move certain workloads to Azure or another cloud. That can make sense for specific apps, but it changes your costs to an ongoing subscription and usually takes more planning. For many small businesses with on-premises file servers, domain controllers, or local apps, a new on-premises server license is simpler.

Which version should you upgrade to?

You can compare every option on our Windows Server licenses page.

Standard or Datacenter: choosing the right edition

Windows Server comes in two main editions for businesses. The difference comes down to virtualization:

• Standard lets you run two virtual machines (or two Hyper-V containers) per fully licensed server, plus the Hyper-V host itself if it’s used only to host and manage those VMs. It’s ideal for physical servers or light virtualization.
• Datacenter lets you run unlimited virtual machines on a fully licensed server. It’s built for heavily virtualized environments.

If you need more than two VMs on one host, you can “stack” additional Standard licenses (each set of two extra VMs needs the server’s cores licensed again), or choose Windows Server 2025 Datacenter for unlimited VMs. A Datacenter version is also available for Windows Server 2022.

One more rule to know: during an upgrade, you can go from Standard to Datacenter, but you can’t go from Datacenter down to Standard.

Windows Server licensing basics: cores and CALs

Windows Server Standard and Datacenter use a per-core plus CAL licensing model. Two pieces matter.

1. Core licenses

When you license by physical cores:

• Every physical core in the server must be licensed.
• There’s a minimum of 8 core licenses per processor and 16 core licenses per server.

2. Client Access Licenses (CALs)

Every user or device that accesses Windows Server needs a Windows Server CAL. You can choose:

• User CALs: one user, accessing from any number of devices. Best when each person uses several devices.
• Device CALs: one device, used by any number of people. Best for shared PCs or shift workers.

For Windows Server 2025, you can add Windows Server 2025 User CALs, or start with the Windows Server 2025 Standard + 5 User CALs bundle. If you’re moving to 2022, see the Windows Server 2022 5 User CAL and 5 Device CAL packs.

Remote Desktop Services (RDS) CALs

If people connect to your server through Remote Desktop to run apps or a full desktop, they also need RDS CALs on top of the regular Windows Server CAL. RDS CALs follow strict version rules:

• Windows Server 2016, 2019, or 2022 RDS CALs can’t connect to a Windows Server 2025 session host.
• Your Remote Desktop license server must run the same version of Windows Server as your RDS CALs, or newer.

If you’re moving a Remote Desktop server to Windows Server 2022, you’ll need Windows Server 2022 RDS CALs. For a 2025 Remote Desktop server, plan for 2025 RDS CALs.

A simple upgrade timeline

You have less than three months before January 12, 2027. Here’s a practical plan:

1. Now (late October to November 2026)

   • List every server running Windows Server 2016, including virtual machines.
   • Write down each server’s roles (file server, domain controller, Remote Desktop, print, apps) and the software running on it.
   • Check with your software vendors that your apps support Windows Server 2025 (or 2022).
   • Count your physical cores, users, and devices so you know how many core licenses and CALs you need.

2. November to December 2026

   • Buy your Windows Server licenses and CALs.
   • Take a full backup of each server and test that you can restore it.
   • Upgrade or migrate a low-risk server first, then test everything.

3. December 2026 to early January 2027

   • Upgrade or migrate the rest of your servers during scheduled maintenance windows.
   • Confirm Windows Update and your security tools are working on the new version.
   • Retire or isolate any Windows Server 2016 machines you can’t move yet, and decide whether ESUs are an option for them.

In-place upgrade or clean install?

In-place upgrade keeps your settings, roles, and data on the same hardware. It’s the fastest path. Before you start, Microsoft recommends:

• A full backup, plus a restore test.
• A planned maintenance window (the server restarts several times).
• A valid product key for the new version. Unlike Windows on PCs, every Windows Server upgrade needs its own license.
• Checking that each role supports an in-place upgrade.

Clean install or migration means setting up the new version fresh (often on new hardware) and moving roles and data over. It takes more effort but gives you a clean, well-documented server. It’s often the better choice if your current hardware is aging.

Don’t forget SQL Server

If your Windows Server 2016 machine also runs SQL Server 2016, note that SQL Server 2016’s extended support already ended on July 14, 2026. If you’re rebuilding the server, it’s a good time to move your databases to a current version too. See our SQL Server licenses.

Frequently asked questions

Get ready before the deadline

January 12, 2027 is close, and server upgrades take planning. The sooner you have licenses in hand, the sooner you can back up, test, and upgrade on your own schedule instead of rushing at the last minute.

Ready to upgrade? Browse our Windows Server licenses, start with Windows Server 2025 Standard, or request a quote if you need help working out how many core licenses and CALs your business needs. Tell us how many servers, cores, and users you have, and we’ll help you put together the right licenses.