Office LTSC 2021, Project LTSC 2021 and Visio LTSC 2021 lose support on 13 October

Office LTSC 2021, Project LTSC 2021 and Visio LTSC 2021 lose support on 13 October

25 September 2026 — Microsoft ends support for Office LTSC 2021 on 13 October 2026, eighteen days from today. Project LTSC 2021 and Visio LTSC 2021 end on the same day. After that date Microsoft provides no security updates, no bug fixes and no technical support for them. Microsoft's lifecycle page has carried the date since April, a university IT department was already warning its users in November 2025, and on 15 September Microsoft told its resellers to contact customers still on these versions.

What changes on 13 October

Nothing stops working on the day. What stops is the flow of fixes: the first security flaw found in these versions after 13 October will not be patched. For software that opens email attachments and documents from outside the organisation all day, that is the main risk, and it grows every month. Microsoft also notes compliance consequences: many security frameworks and insurance questionnaires ask whether all software is supported.

Two related points from Microsoft's notice to resellers are worth knowing. Microsoft 365 Copilot works only with the cloud-connected Office apps in Microsoft 365 plans, not with any on-premises version. And the Azure Information Protection labelling client for perpetual Office has already been retired.

Who is affected

Organisations that bought Office, Project or Visio as a one-off LTSC 2021 licence, usually because of regulation, a lack of internet connectivity, or a preference for not subscribing. Specialist environments, such as laboratories, factory floors and regulated offices, are the most likely to still have it.

The supported routes

• Microsoft 365 Apps, as part of a Microsoft 365 plan: Microsoft names Microsoft 365 E3 for enterprises and Microsoft 365 Business Premium, Business Standard or Apps for business for organisations with fewer than 300 users.
• Planner and Project Plan 3 and Visio Plan 2 replace Project and Visio LTSC in the cloud.
• Office LTSC 2024, Project LTSC 2024 and Visio LTSC 2024, for organisations that must stay on-premises.

What to do

• Find every device still running the 2021 LTSC versions. Your software inventory or device management tool should list them.
• Decide, per group of users, between a Microsoft 365 plan and the 2024 LTSC versions, and budget for it. Moving to a subscription changes the cost from a one-off to a recurring one.
• Where a device genuinely cannot be upgraded by 13 October, record the exception, limit what that device can open from outside, and set a date to remove it.
• If you buy Microsoft licences through a reseller, ask for a quote now rather than in October.

Sources

• Microsoft Lifecycle: Office LTSC 2021 reaching end of support on October 13, 2026 — 22 April 2026
• Microsoft Partner Center announcements, September 2026: Office LTSC 2021 end of support — 15 September 2026
• Washington State University Information Technology Services: End of support for Office LTSC 2021, October 2026 — 14 November 2025