If your business still runs Office 2021, the deadline is no longer a future IT project. Microsoft support ends on 13 October 2026 — giving organisations only a short window to identify affected users, test their options and make a safe transition plan.

Office 2021 applications will not suddenly stop opening on that date. The risk is what happens next: Microsoft will no longer provide security updates, bug fixes or technical support for the product. Unsupported productivity software becomes harder to secure, harder to troubleshoot and increasingly difficult to defend during a compliance or cyber-insurance review.

What Is Reaching End of Support?

The October deadline applies to Office 2021 and Office LTSC 2021. It also affects related long-term-service products, including Project LTSC 2021 and Visio LTSC 2021. Microsoft has published the same end-of-support date for these products: 13 October 2026.

End of support does not mean the software is immediately unusable. It means that continuing to use it becomes the organisation's responsibility without the normal security and vendor-support safety net.

Why This Is a Business Risk, Not Just an IT Upgrade

Office is connected to email, identity, document stores, browsers, line-of-business systems and shared information. A vulnerable or unsupported application on one endpoint can create a route into data that the business is required to protect.

Security exposure: newly discovered vulnerabilities will not receive the same protection as supported versions.
Operational risk: future Windows, browser, add-in or cloud-service changes may introduce compatibility problems.
Compliance pressure: POPIA, ISO 27001 and customer assurance processes expect organisations to manage software lifecycle and known vulnerabilities.
Recovery risk: resolving an outage or compatibility issue becomes slower when the vendor no longer supports the version in use.
Inconsistent estates: unmanaged exceptions make patching, support and user training more difficult.

First: Find Out Who Is Actually Affected

Do not rely on memory or a few familiar machines. Build an inventory that covers office workers, remote users, shared workstations, branch offices, terminal servers and devices used by contractors.

For each device or user, record the Office edition, installation type, operating system, licence ownership, business-critical add-ins, macros, templates and integrations. Include Project and Visio installations: these are often missed because they are used by a smaller specialist group.

Choose the Right Path

For most organisations, the main options are moving to Microsoft 365 Apps or upgrading to a supported perpetual Office release where that better fits the environment. Microsoft 365 Apps provides an ongoing update path and works particularly well where the business already uses Microsoft 365 identity, email, collaboration and cloud storage.

A perpetual licence may still be appropriate for a controlled or specialised environment, but it should be a deliberate decision based on application compatibility, connectivity, support requirements and lifecycle planning — not simply a way to postpone the same conversation.

Some regulated or operational environments may need to retain a legacy installation temporarily. If so, document the reason, isolate the exception where possible, restrict access, monitor it closely and assign an owner and removal date.

The 30-Day Readiness Checklist

Inventory the estate: identify Office, Project and Visio versions across every location and device.
Classify business impact: identify executives, finance teams, client-facing users and specialist applications that need priority testing.
Test compatibility: validate macros, add-ins, templates, document workflows, printing and integrations before changing user devices.
Confirm identity controls: check MFA, conditional access, device compliance and privileged access before moving users to a new sign-in experience.
Pilot the change: start with a representative group, capture issues and update the deployment plan.
Communicate clearly: tell users what will change, when it will happen and how they get help.
Roll out in waves: schedule migrations around payroll, month-end, client deadlines and other operational constraints.
Close the exceptions: record any remaining Office 2021 devices, apply compensating controls and set a firm retirement date.

Do Not Wait for the Deadline

A rushed upgrade creates avoidable disruption. A planned transition gives the business time to test critical workflows, protect data, train users and make an informed licensing decision. It also gives IT teams evidence that software lifecycle risk is being actively managed.

If you do not know how many Office 2021 installations remain in your environment, that is the first finding to resolve. The safest next step is a structured assessment of your devices, applications, identities and data flows — followed by a prioritised migration plan.

Office 2021 Support Ends on 13 October: The 30-Day Business Readiness Checklist