The October 2026 Microsoft Deadline: What UK Businesses Need to Know
Three Microsoft deadlines are landing on the same day this October, and here's what to do about it;
Most software updates arrive quietly, one at a time. This October, several land on the same date.
On 13th October 2026, Office 2021 loses support, Windows 11 version 24H2 stops receiving updates for Home and Pro editions, and the first year of paid Windows 10 security updates runs out - all at once.
None of it needs to be a crisis.
But it does need a plan before October, not during it.
What's actually changing on 13 October 2026?
Three separate things reach the same deadline:
Office 2021 and Office LTSC 2021 stop receiving security updates and technical support entirely
Windows 11 version 24H2 (Home and Pro editions) reaches the end of its servicing window and stops receiving updates
Windows 10 Extended Security Updates, Year 1 expires - relevant if your business paid for the extra year of security patches after Windows 10's free support ended in October 2025
A few weeks later, Windows 11 version 23H2 Enterprise and Education editions follow, reaching end of support in mid-November.
Why does it matter if my software still opens and works?
Because "end of support" doesn't mean the software stops working.
It means Microsoft stops fixing it.
No more security patches for newly discovered vulnerabilities, no bug fixes, no technical support if something breaks.
That's a bigger deal than it sounds.
New vulnerabilities get found in old software constantly, and once support ends, they stay open as nobody's patching them anymore. Running unsupported software isn't an immediate failure, but every week past the deadline is a week of accumulating, unpatched risk, with nobody watching for it.
If you're working toward or holding Cyber Essentials certification, running out-of-support software is also directly at odds with what the assessment checks for.
What if I'm still on Windows 10?
If your business paid for a year of Extended Security Updates after the free support window closed last October, that paid year runs out on the same 13th October 2026 date. From there, the choices are the same ones you had last year, just with less runway, either pay again for a second year of ESU (typically at a higher cost than year one), upgrade eligible machines to Windows 11, or replace hardware that can't make the jump.
Not every Windows 10 machine can upgrade.
Windows 11 has stricter hardware requirements, so part of the job is working out which devices are eligible and which genuinely need replacing.
What if I'm on Office 2021 or Office LTSC 2021?
Office 2021 was often bought specifically as a one-off purchase, rather than a subscription which is appealing if you wanted to avoid ongoing licensing costs. Once support ends in October, that trade-off changes - you keep the one-off cost, but lose the ongoing security patching that made it a reasonable choice in the first place.
The realistic paths from here are moving to Microsoft 365, or replacing it with the newer Office LTSC 2024 if you specifically want to keep a one-off licence model rather than a subscription.
What should you do before October?
Audit what you're actually running — most businesses don't have an accurate, current list of every device's operating system version and every machine's Office version without checking directly
Work out which Windows 10 machines can upgrade to Windows 11, and which need replacing — this takes longer to plan and budget for than people expect
Decide your Office path before the deadline, not after — moving to Microsoft 365 involves some setup and staff adjustment, better done on your own timeline than in a rush
Start now, not in September — the businesses that treat this as a summer project rather than an October emergency spend less and cause less disruption to their own team
How RefynIT can help
This is exactly the kind of change that's easy to lose track of; a handful of separate deadlines, on different products, converging on one date that's easy to file under "later" until it's suddenly this month's problem.
Our managed IT support includes exactly this kind of proactive tracking as standard.
Knowing what's running across your business, what's approaching end of support, and getting ahead of it well before the deadline rather than reacting once something's already unsupported.
If your business runs on Microsoft 365, that includes keeping your licensing and setup properly aligned with what Microsoft's actually supporting, not just what happens to still work.
Get in touch and we'll check exactly where your business stands before October.
