A plain-English guide for Australian businesses to the end of support for Office 2021 on 13 October 2026. Covers exactly what happens on the date (the apps keep working but stop getting security updates, with no ESU lifeline unlike Windows 10), which apps are affected, why running unsupported Office is a security, compliance and insurance risk, and the real options: Microsoft 365 Business Premium (recommended for most, bundling Office with Defender, Intune and Entra), Office LTSC 2024 (perpetual but commercial-only and supported only to 2029), or doing nothing. Notes that this lands the same month as Windows 10 ESU year one, creating an October 2026 double deadline.
Office 2021 end of support: what October 2026 means for your business
On 13 October 2026, Office 2021 reaches end of support. The apps will still open, which is exactly why this one catches people out. Here is what actually changes, and the choice every business on perpetual Office now has to make.
The short version
Office 2021 stops receiving security updates on 13 October 2026. The apps keep working, but from that day any new vulnerability in Word, Excel or Outlook stays unpatched forever. And unlike Windows 10, there is no paid extension to buy more time.
If you bought perpetual Office to escape subscriptions, you are back at the same fork. Move to Microsoft 365, or buy another perpetual licence (Office LTSC 2024) that only delays this to 2029.
For most Australian SMEs, Microsoft 365 Business Premium is the sensible move. It keeps Office current and bundles in the security most businesses are missing, for not much more than Office alone.
What actually happens on 13 October 2026
On that date, every version of Office 2021 reaches end of support. That covers Office Home & Business 2021, Office Professional 2021 and the volume-licensed Office LTSC 2021, across both Windows and Mac. The apps affected are the usual suspects: Word, Excel, PowerPoint, Outlook, Access, OneNote and Publisher, plus Visio 2021 and Project 2021.
End of support does not mean the software switches off. Your copies of Word and Excel will open on 14 October exactly as they did the day before. What ends is everything behind the scenes: no more security updates, no bug fixes, and no help from Microsoft if something breaks. The app looks fine, and that is the trap. It carries on working while quietly turning into an unpatched liability.
There is no Extended Security Updates program for Office. Windows 10 users can pay for ESU to buy breathing room. Office 2021 has no equivalent. When the date passes, the security updates are simply gone.
Why running unsupported Office is a real problem
No more security updates
Office documents are a favourite delivery route for attackers. Once the patches stop, every new flaw found in Word, Excel or Outlook stays open on your machines for good.
Compliance and insurance gaps
Running unsupported software can breach the security requirements in your cyber insurance policy and in frameworks like the Essential Eight, which expects vendor-supported, patched applications.
Creeping incompatibility
File formats, add-ins and cloud services keep moving. Over time an old Office drifts out of step with the people and systems you work with every day.
Office files are one of the most common ways attackers get in, which is why unpatched Office is not a small loose end. It sits right in the path our ransomware deep dive describes, and it is exactly the kind of gap the Essential Eight is built to close.
Your options, honestly compared
There are really three paths from here. Two of them keep you supported. One of them is a slow-motion problem.
Microsoft 365 Business Premium
The Office apps you know, always kept current, bundled with the security stack most SMEs are missing: Defender, Intune device management, and Entra identity protection. One subscription covers the lot.
Office LTSC 2024
A one-off perpetual licence supported until October 2029. It suits genuinely offline or locked-down machines, but it is commercial-only, a subset of what Microsoft 365 offers, and it simply pushes this same decision three years down the road.
Do nothing
The apps keep opening after October 2026, which is exactly what makes this dangerous. They quietly become an unpatched hole in an otherwise reasonable setup, and nobody notices until something goes wrong.
The October 2026 squeeze
Office 2021 is not the only clock running out this month. Windows 10 reached its own end of support in October 2025, and the first year of paid Extended Security Updates, the stopgap many businesses leaned on, runs out around the same mid-October point in 2026. So plenty of Perth businesses are looking at an ageing operating system and an unsupported Office suite at the same moment.
That is annoying if you treat each as a separate scramble. It is an opportunity if you plan them together. Moving to Microsoft 365 and a current, supported Windows in one coordinated step is cheaper, cleaner and less disruptive than doing two rushed migrations back to back. This is the kind of thing worth mapping out now, while October is still months away rather than next week.
The takeaway
Office 2021 reaching end of support is not a crisis, but it is a decision you cannot quietly skip. The apps keep working, so nothing forces your hand, which is precisely why so many businesses will drift past October with an unpatched Office and not realise until it matters.
For most, the honest answer is Microsoft 365 Business Premium: current Office plus the security layer you were probably going to need anyway. If perpetual really is non-negotiable, LTSC 2024 buys you to 2029. Either way, the move is far less painful when it is planned rather than rushed. That planning, and the migration itself, is exactly what our team does day in, day out.
Common questions
Will Office 2021 stop working on 13 October 2026?
No. The apps will keep opening and your files will still be there. What stops is support: no more security updates, bug fixes, or help from Microsoft. That is the real risk, because the software keeps running while quietly becoming unpatched and exposed.
Is there an ESU program for Office 2021 like there is for Windows 10?
No. This is the important difference. Windows 10 has a paid Extended Security Updates option that buys you extra time. Office 2021 has no such lifeline. When support ends on 13 October 2026, that is the end of the road for security updates, full stop.
We bought perpetual Office to avoid subscriptions. What now?
You have two real choices. Move to Microsoft 365, which keeps Office current and adds the security tools most businesses are missing, or buy Office LTSC 2024 as another perpetual licence supported until 2029. The second option avoids the subscription but only delays this same decision, and it does not include the security layer. For most Australian SMEs, Microsoft 365 Business Premium is the better value once you count what it bundles in.
Which Office apps are affected?
All the Office 2021 apps: Word, Excel, PowerPoint, Outlook, Access, OneNote and Publisher, plus Visio 2021 and Project 2021. The same 13 October 2026 date applies across the Office 2021 family, on both Windows and Mac.
Does this affect Microsoft 365 subscribers?
No. If you are already on a Microsoft 365 plan, your Office apps update automatically and there is nothing to do here. This deadline only affects the one-off perpetual versions: Office 2021 (and Office 2019, which reached its own end of support just before it).