Windows Server 2016 reaches the end of extended support on 12 January 2027. After that date Microsoft stops releasing security updates for it unless you pay for Extended Security Updates. Windows 10 already reached end of support on 14 October 2025, and Windows Server 2012 R2's last paid update year ended in October 2026. ERS IT Solutions, based in Dublin 15 since 1983, plans and runs these upgrades for Irish businesses.
When does Windows Server 2016 end of support happen?
Windows Server 2016 extended support ends on 12 January 2027, according to Microsoft's lifecycle page. Mainstream support already ended in January 2022. The date covers the Datacenter, Essentials, MultiPoint Premium and Standard editions. After it, there are no free security updates.
Microsoft's 2027 end of support list also includes Hyper-V Server 2016, IIS 10 on Windows Server 2016 and Windows Server Update Services for Windows Server 2016 on the same date. If your office still has a 2016 server running file shares, a line-of-business application or Active Directory, it needs a plan now.
Key Microsoft end of support dates for Irish businesses
These are the dates most small and mid-sized firms in Ireland run into, taken from Microsoft's own lifecycle pages:
| Product | End of support | Source |
|---|---|---|
| Windows 10 (all main editions) | 14 October 2025 | Microsoft |
| Office 2016 and Office 2019, Exchange Server 2016 and 2019 | 14 October 2025 | Microsoft |
| SQL Server 2016, SharePoint Server 2016 and 2019 | 14 July 2026 | Microsoft |
| Windows Server 2012 and 2012 R2, final ESU year | 13 October 2026 | Microsoft |
| Office 2021 and Office LTSC 2021 | 13 October 2026 | Microsoft |
| Windows Server 2016 | 12 January 2027 | Microsoft |
| Windows 10 commercial ESU, year 3 | 10 October 2028 | Microsoft |
| Windows Server 2019 | 9 January 2029 | Microsoft |
Microsoft publishes these dates in Pacific Time, so the cut-off in Ireland falls early on the following morning.
What happens when Windows Server reaches end of support?
The server keeps running, but Microsoft stops releasing security fixes, bug fixes and technical support for it. Any new vulnerability found after that date stays open. Newer software and backup tools also gradually stop supporting it. For a server holding company files or customer data, that is a security and data protection risk.
Ireland's National Cyber Security Centre is direct about this in its small business guidance: if the manufacturer stops offering support for the hardware or software you use, it is time to replace it with a more up-to-date alternative.
Can you get Extended Security Updates for Windows Server 2016?
Yes. Microsoft announced Extended Security Updates for Windows Server 2016 in February 2026, delivered through Azure Arc. ESUs are a paid, temporary bridge. Microsoft describes them as a last resort covering critical and important security updates for up to three years, with no new features and no general technical support.
For Windows Server 2012 and 2012 R2, Microsoft priced on-premises ESUs at 100% of the full licence price for each year, and ESUs were free for servers moved into Azure. Check Microsoft's ESU FAQ for current Windows Server 2016 terms before budgeting.
Windows 10 end of support: what Irish businesses need to know
Windows 10 support ended on 14 October 2025. Businesses can buy Extended Security Updates for Windows 10 at $61 per device for year one, with the price doubling each year for a maximum of three years. Year two cannot be bought without year one. ESU is included at no extra cost for Windows 10 running in Windows 365 and Azure Virtual Desktop.
The consumer ESU scheme is different. In the European Economic Area, home users could enrol at no cost while signed in with a Microsoft account, with coverage to 12 October 2027. That scheme is for personal use. Business PCs should go through the commercial programme or, better, move to Windows 11.
What are your options for an old Windows server?
You have four realistic options for a server on Windows Server 2016 or older: upgrade it, replace it, move the workload to the cloud, or buy Extended Security Updates while you do one of those. Which one fits depends on what the server does, how old the hardware is and whether the software on it can move.
- Upgrade in place or rebuild on a supported Windows Server version, if the hardware is recent enough.
- Replace the hardware and migrate roles to a new server.
- Move the workload to the cloud. File shares often move to SharePoint and OneDrive. Email moved off Exchange Server years ago for most firms. Applications can go to Azure.
- Buy ESUs for a short, fixed period while one of the above is done.
ERS has done this work for years. For Excel Industries, ERS replaced end-of-life servers and live-migrated 35 users with minimal disruption, taking the backup window from 12 hours to a recovery time measured in minutes. For Communicare, ERS moved an on-premise file server to SharePoint Online.
How to plan a Windows 10 and Windows Server upgrade
A good plan starts with an inventory, not a purchase order. List every PC and server, its operating system, hardware age and what it does, then decide upgrade, replace or retire for each one. Test critical applications on the new version before the move, and schedule cutovers outside business hours.
- Inventory. Every device, operating system version and support end date.
- Check hardware. Many older PCs cannot run Windows 11. Those need replacing, not upgrading.
- Check applications. Ask software vendors which versions they support.
- Decide per server. Upgrade, replace, move to cloud or retire.
- Budget. Hardware, licences, project time, and ESU only if a deadline cannot be met.
- Pilot. Move a small group first.
- Roll out and document. Record what changed and update your asset list.
For PCs, Microsoft's modern tools make the rollout faster. Windows Autopilot can set up a new laptop for a user with little hands-on work, and Intune keeps it managed afterwards. See Microsoft Modern Workplace.
Does running unsupported Windows affect cyber insurance or compliance?
It can. Insurers and frameworks increasingly ask whether your systems are patched and supported. The Cyber Essentials requirements say software must be licensed and supported, removed when it becomes unsupported, and have high-risk and critical updates installed within 14 days of release. Read your insurance policy wording and ask your insurer directly.
ERS holds Cyber Essentials certification and helps clients prepare for their own. See Cyber Essentials in Ireland and cyber security compliance.