When does Office 2021 support end? What it means if you’re still using it

Mid-October is shaping up to be one of the busiest weeks in Microsoft’s calendar for years. On 13 October 2026 (October’s Patch Tuesday), a whole group of widely used products stops receiving security updates. None of them will stop working overnight, but from that day on, every new vulnerability found in them stays open for good.

Here’s what’s changing, who it affects and a simple checklist you can run through with your team this week.

Is Office 2021 still safe to use after 13 October?

Office 2021 (Word, Excel, Outlook, PowerPoint and the rest) reaches end of support on 13 October 2026. Microsoft has confirmed there will be no extension and no extended security updates. The apps will keep opening, but there will be no more security fixes, bug fixes or technical support.

The volume-licensed version is in the same boat. Office LTSC 2021 also reaches end of support on 13 October 2026, and Microsoft warns that continuing to run it could increase your security risk and affect compliance. Visio LTSC 2021 and Project LTSC 2021 retire on the same date.

What should you move to?

For most businesses, the answer is Microsoft 365 Apps. These are the always-up-to-date versions of Word, Excel and Outlook included in Microsoft 365 Business Standard and Business Premium. There’s no fixed end date to worry about, and it’s the version that gets Copilot and new features. If you genuinely need a one-off licence with no subscription, Microsoft’s recommended path is Office LTSC 2024.

Our managed Microsoft 365 service handles the licensing, rollout and migration, so the switch happens without disrupting your day.

What happens to Microsoft Publisher?

Publisher has already gone. Microsoft stated that Microsoft 365 subscribers could only use Publisher until 1 October 2026. After that, it’s no longer included in Microsoft 365 and subscribers can’t open or edit files in it. Perpetual versions will still run, but lose all support on 13 October.

If your team still produces newsletters, flyers or menus in Publisher, the quickest fix is to save important .pub files as PDF, then open them in Word to edit. Microsoft suggests Word and PowerPoint for most of what Publisher used to do, from branded templates to business cards and calendars. Complex layouts may need some tidying up after conversion, so start with the files you use most.

Are you still running Windows Server 2012 or 2012 R2?

This is the one that worries us most. Windows Server 2012 and 2012 R2 left extended support back in October 2023, and have only been patched since through paid Extended Security Updates. According to Microsoft’s lifecycle FAQ, that programme runs for a maximum of three years, and the third year ends on 13 October 2026.

There’s no year four, on-premises or in Azure. Any server still running 2012 after that date is permanently unpatched, and servers are exactly the kind of system attackers look for. That old box in the comms cupboard running your accounts package or file shares needs a plan now.

What are the options?

You can upgrade in place to a supported version of Windows Server, rebuild on new hardware, or move the workload off the server entirely. For many SMEs, the simplest route is application hosting or private cloud, with no more ageing hardware to replace every few years.

What about Windows 10?

Windows 10 lost standard support in October 2025, and many businesses bought Extended Security Updates to buy time. Microsoft sells business ESU one year at a time, for a maximum of three years, and Year 1 ends on 13 October 2026. If you haven’t renewed for Year 2, those PCs stop getting patches. The price goes up each year, so this is a good moment to weigh renewal against simply replacing the machines with Windows 11 devices.

What should you check in your office this week?

Run through this list. It takes less time than you’d think:

• Office versions: open Word, go to File > Account and check the product name. If it says 2021 or LTSC 2021, it needs replacing.
• Publisher files: find any .pub files your team still relies on and convert them to PDF or Word.
• Servers: list every server and its Windows version. Anything on 2012 or 2012 R2 needs a migration plan.
• Windows 10 PCs: confirm which machines are enrolled in ESU and whether Year 2 is paid for, or book them in for Windows 11.
• Hidden dependencies: check line-of-business apps, scanners and printers that might rely on older versions before you upgrade.
• Compliance: unsupported software can cause a Cyber Essentials failure, so make sure everything in scope is supported before your next renewal.

Why does unsupported software matter so much?

Once support ends, attackers know every newly discovered flaw will stay open forever. Unsupported software is one of the most common routes into a business. It’s also an automatic fail under Cyber Essentials, which requires all in-scope software to be licensed and supported, and it can put cyber insurance cover at risk too.

The good news is that none of this has to be a scramble. A quick audit tells you exactly what’s affected, and most upgrades can be planned around your working week. If you’re not sure where you stand, our managed IT support team can check your estate against every October deadline. Or start with a free security risk assessment and get a clear picture before the 13th.