Microsoft support for Office 2021 ends on 13 October 2026. The same deadline applies to Office LTSC 2021, Project LTSC 2021 and Visio LTSC 2021. The programs will not suddenly stop opening, but Microsoft will no longer provide security updates, bug fixes or technical support. Businesses should identify affected installations and agree an upgrade plan now.
The deadline is particularly important for small businesses that bought Office as a one-off purchase and have continued using it without a Microsoft 365 subscription. A computer can look fully operational while its Office software is moving out of support.
What is Microsoft changing?
Microsoft is ending support for the 2021 generation of its perpetual Office products. According to Microsoft’s 15 September 2026 Partner Center announcement, Office LTSC 2021, Project LTSC 2021 and Visio LTSC 2021 will stop receiving updates, security fixes and technical support after 13 October 2026.
Microsoft’s separate guidance for ordinary Office 2021 installations confirms the same deadline:
“There will be no extension and no extended security updates.”
That means businesses cannot pay Microsoft to keep the 2021 edition patched for longer. They need to move affected installations to a supported product.
When does Office 2021 support end?
Support ends on 13 October 2026. Businesses should complete their assessment before that date, allowing time to check licences, test important documents and add-ins, and deploy a supported replacement.
| Product | End-of-support date | After the deadline |
|---|---|---|
| Office 2021 | 13 October 2026 | No security updates, bug fixes or Microsoft support |
| Office LTSC 2021 | 13 October 2026 | No security updates, bug fixes or Microsoft support |
| Project LTSC 2021 | 13 October 2026 | No security updates, bug fixes or Microsoft support |
| Visio LTSC 2021 | 13 October 2026 | No security updates, bug fixes or Microsoft support |
Who is affected by the Office 2021 deadline?
The deadline affects businesses using Office 2021 or Office LTSC 2021 on Windows or Mac, together with the 2021 LTSC editions of Project and Visio. It may include computers supplied with a one-off Office licence, shared workstations and specialist devices that were deliberately kept outside the Microsoft 365 Apps update model.
Businesses already running a supported version of Microsoft 365 Apps are not affected by this particular Office 2021 deadline. However, Project or Visio may have been purchased separately, so those products still need checking.
On a Windows computer, open Word or Excel and select File → Account. The Product Information section normally identifies the installed edition. If several computers are involved, ask your IT provider to produce an inventory rather than checking every machine manually.
What will users notice after 13 October 2026?
Most users may notice nothing immediately. Microsoft says Office 2021 applications may continue to function after support ends. The important change is that newly discovered security weaknesses will not be fixed and Microsoft will no longer supply bug fixes or technical support.
That quiet transition makes unsupported software easy to overlook. Staff may continue opening Word documents, spreadsheets and email while the business accumulates security, reliability and compliance risk in the background.
Why does unsupported Office matter to a UK SME?
Office files and Outlook email are common routes for malicious links, attachments and document-based attacks. Once a version stops receiving security fixes, a newly discovered vulnerability may remain exposed permanently on affected computers.
Unsupported software can also complicate cyber insurance questionnaires, customer security reviews and compliance obligations. It does not automatically mean a business has suffered a breach, but it becomes harder to demonstrate that systems are being maintained appropriately.
The deadline may coincide with other device work. Businesses should also check whether any machines are approaching a Windows support deadline; our guide explains the separate Windows 11 24H2 end-of-support date.
What are the replacement options?
For most small businesses, Microsoft recommends moving to Microsoft 365 Apps. Where a device genuinely needs a fixed, on-premises release, Microsoft identifies Office LTSC 2024 as the supported alternative. The right answer depends on licensing, internet access, update requirements and compatibility with business-critical software.
| Option | Best suited to | Important consideration |
|---|---|---|
| Microsoft 365 Apps | Most connected business users | Subscription licensing with continuing security and feature updates |
| Office LTSC 2024 | Specialist, regulated or restricted devices | One-device volume licence with a fixed feature set |
| Project or Visio subscription | Users who need those specialist applications | Licensed separately from many Microsoft 365 business plans |
Do not buy licences before checking what the business already owns. Some Microsoft 365 plans already include the desktop Office applications, while others do not. Our Microsoft 365 licensing guide for businesses explains the practical differences.
What should businesses do before the deadline?
Start with an accurate inventory, then test the applications and documents that matter before replacing anything. A planned upgrade is normally straightforward; a rushed change after a security or compatibility problem is not.
- Identify every Office installation. Include laptops, shared computers, remote devices and seldom-used machines.
- Check Project and Visio separately. They may have different licences from the main Office suite.
- Review the Microsoft 365 licences already assigned. Some users may already be entitled to install supported Microsoft 365 Apps.
- Test important add-ins and macros. Accounting, document-management and line-of-business integrations deserve particular attention.
- Confirm device compatibility. Check the operating system, storage and any restrictions on receiving updates.
- Plan deployment and user communication. Avoid changing every device without a tested route back.
- Remove unsupported copies. Leaving an old edition installed alongside its replacement can create confusion and risk.
Microsoft provides detailed upgrade planning guidance for older Office versions, including application compatibility and deployment considerations.
Microsoft 365 and Office planning
Still running Office 2021?
KES can identify affected computers, review the licences you already have and plan a supported replacement before the 13 October deadline.
- Office, Project and Visio version checks
- Microsoft 365 licence review
- Add-in and application compatibility planning
- Managed deployment with user support
Need a clear answer before upgrading?
Tell us what your business is running and we will help you identify the practical next step.
Contact KES →What happens if a business does nothing?
The applications may keep opening, but the installation becomes unsupported. Any security flaw discovered after 13 October 2026 may remain unpatched, and Microsoft will not provide ordinary technical support or bug fixes for the affected product.
Waiting can also turn a controlled licensing and deployment exercise into an urgent support problem. A later Windows update, third-party integration change or security requirement may expose compatibility issues when the business has less time to test alternatives.
Do Project 2021 and Visio 2021 need upgrading too?
Yes, if the business uses the LTSC 2021 editions. Microsoft’s latest partner notice gives Project LTSC 2021 and Visio LTSC 2021 the same 13 October 2026 end-of-support date. Subscription replacements include Planner and Project Plan 3 or Plan 5, and Visio Plan 2; supported perpetual 2024 editions are also available for appropriate scenarios.
Project and Visio should be assessed separately because they are often installed only for particular employees, making them easier to miss during a general Office review.
Quick answers
Will Office 2021 stop working on 13 October 2026?
No. Microsoft says the applications may continue to function, but they will no longer receive security updates, bug fixes or technical support.
Is there an extended security update programme for Office 2021?
No. Microsoft states that there will be no extension and no extended security updates for Office 2021.
Does Microsoft 365 Apps stop working on the same date?
No. Supported Microsoft 365 Apps installations follow Microsoft’s continuing update model and are not ending on this Office 2021 deadline.
Should every business move to a Microsoft 365 subscription?
Microsoft 365 Apps is the recommended route for most businesses, but Office LTSC 2024 remains an option for specific regulated, offline or restricted devices.
How can we tell whether we are affected?
Check the Product Information shown under File → Account in an Office application, or ask your IT provider to inventory installed Office, Project and Visio versions across all managed computers.
The important point
Office 2021’s end of support is close enough to require action now. Businesses have until 13 October 2026 to identify affected computers, confirm the right licensing route and test any important add-ins or macros.
If you are unsure which versions or licences your business has, contact KES before buying replacements. A short assessment can prevent unnecessary licence costs and reduce disruption during the change.
Microsoft sources
- Microsoft Partner Center: September 2026 announcements
- Microsoft Lifecycle: Office LTSC 2021 reaching end of support
- Microsoft Support: End of support for Office 2021
- Microsoft Learn: Plan an upgrade from older versions of Office
Checked 16 September 2026. Microsoft can update product guidance, so organisations should confirm current information before making licensing or deployment decisions.
