Two things in your office stop getting security updates on October 13

Press the Windows key, type winver, and press Enter. If the box that pops up says Version 24H2, that computer stops getting security updates on October 13 — eleven days from now.

Many of the PCs that left Windows 10 before its deadline last October landed on 24H2, because it was the current version at the time. Two years after its release, it is the one running out. Microsoft says it is moving Home and Pro PCs that no IT department manages onto 25H2 automatically, so many will already have moved. The ones worth finding are the ones that didn't: updates paused, a restart postponed for months, or a PC kept on someone else's update schedule.

Windows 11 expires by version, not by name

The confusing part is that "we're on Windows 11" tells you nothing about whether you're still being patched. Microsoft puts each yearly version on its own clock: 24 months of support for Home, Pro, Pro Education and Pro for Workstations, and 36 months for Enterprise and Education. Small offices are almost always on Home or Pro.

So on Microsoft's own release table, version 24H2 ends updates on October 13, 2026 for Home and Pro — while the very same version on an Enterprise license runs until October 2027. Version 25H2 is supported until October 12, 2027, and 26H2, which Microsoft began releasing on September 29, until October 10, 2028.

The fix is free and it is not a new computer. Either one arrives as a feature update through Settings → Windows Update. 26H2 is going out in phases, so many PCs will be offered 25H2 for now, and both put you back on a supported version. (You may also see 26H1 mentioned; Microsoft's release notes say it is scoped to new devices shipping this year and is not offered as an in-place update to existing machines.)

The other one: the Office you bought once

Office 2021 reaches end of support on exactly the same day, and this is the one that catches people out.

It isn't Microsoft 365 — a subscription keeps updating itself indefinitely, which is rather the point of paying monthly. This is the other Office: bought once, often bundled with the computer, showing up as Office Home & Business 2021 or Office Professional 2021. Microsoft's lifecycle page puts its retirement at October 13, 2026, covering Home & Student, Home & Business, Professional, and both Mac editions. Office LTSC 2021, the volume-licensed version an IT provider may have installed, ends the same day.

Telling the two apart takes about thirty seconds. Open Word, click File, then Account. If it says "Microsoft 365 Apps for business," you're fine. If there's a year in the product name — 2021 — that install stops getting security fixes.

And here the comparison with Windows 10 matters. Windows 10 has a paid extension: $61 per computer for the first year, doubling every consecutive year, up to three. Microsoft's lifecycle pages list no equivalent programme for Office 2021. The apps will keep opening on October 14. They just stop getting fixed, permanently, and the route forward is a Microsoft 365 subscription or the newer one-time purchase, Office 2024 (sold through volume licensing as Office LTSC 2024).

That gap matters more in Outlook, Word and Excel than almost anywhere else on the machine, because those three are what open the files that strangers email you.

Nothing breaks on the 14th

No screen goes dark. The cost is quiet and cumulative: every month after that date, Microsoft publishes what it found and fixed, attackers read the same notes, and a machine that never received the fix stays open to a problem that is now publicly documented. A year of that stacks up.

Worth knowing too: if you are still running Windows 10 anywhere, the free extra year Microsoft announced applies to personal devices only — company-managed PCs are on the paid track.

This week

1. Run winver on every PC — about ten minutes for a small office. Anything reporting 24H2 needs the update to 25H2 or 26H2. If Windows Update hasn't offered one yet, the "Check for updates" button usually shakes it loose.
2. Check Word → File → Account on each machine — thirty seconds each. You're looking for a year in the name. Note which machines have it; that's your Office budget conversation, and it's cheaper to have it in October than after a December incident.
3. If an outside IT provider manages your computers, ask by name: "Will every PC be off Windows 11 24H2 before October 13, and do we have any Office 2021 installs left?" Someone on top of it answers both in one line. A vague answer is itself an answer.

Keeping versions current is the straightforward half of this. The harder half is knowing when something you already run quietly turns into a problem — which is what our Vulnerability Watch is for: an email on the day a new flaw affects the technology your business actually uses.