Office 2021 reaches end of life on October 13, 2026, when Microsoft stops releasing security updates for Office 2021 and Office LTSC 2021, so every computer still running those versions needs an upgrade plan this week. The apps will keep opening files after that date, which is why the deadline is so easy to miss. WEBIT Services recommends finishing the switch before the deadline, starting with the computers that open email attachments and files from outside the company.
Picture the result a month from now. A spreadsheet arrives from a vendor, someone opens it in Excel 2021, and the vulnerability it targets will never receive a fix. The steps below show which versions are affected, how to find them, and which upgrade path fits.
What does Office 2021 end of support change?
After October 13, 2026, Microsoft will stop providing security updates, bug fixes and technical support for Office 2021 and Office LTSC 2021, according to Microsoft’s lifecycle announcement (updated April 2026). Microsoft’s Office 2021 support page (June 2026) confirms the apps “may continue to function,” and Microsoft is retiring the online help content for those versions as well.
The risk grows from the day the patches stop. Attackers increasingly get in through known software flaws: the Verizon 2026 Data Breach Investigations Report found that exploiting vulnerabilities was the initial access route in 31 percent of breaches, up from 20 percent the year before. Microsoft also notes that the change could affect your compliance requirements.
Which Office versions reach end of support on October 13, 2026?
Two groups of Office products lose support on October 13, 2026:
- Office LTSC 2021. The volume-licensed version businesses buy once, including Standard and Professional Plus editions.
- Office 2021 retail editions. One-time purchases such as Office Home & Business 2021 and Office Home & Student 2021, often bought for a single new laptop.
Microsoft 365 Apps, the subscription version that comes with Microsoft 365 Business Standard and Business Premium, keeps receiving updates as long as the subscription is active. If your team signs in to Office with a work Microsoft 365 account and the apps update on their own, those machines are already on a supported version.
Finding every computer still running Office 2021
A software inventory from your endpoint management tool is the fastest way to find every copy of Office 2021, since it lists installed applications by version on each device. Without one, work through this sequence:
- Pull the software inventory from your remote monitoring and management tool, filtered for Office 2021 and Office LTSC 2021.
- On any machine the inventory misses, open any Office app, select File, then Account, and check the product name under Product Information.
- Match each copy to how it was bought: a one-time retail or volume license, or a Microsoft 365 subscription.
- Flag computers too old to run a current version, since those need a hardware decision first. The guide to hardware lifecycle planning covers when to replace and when to wait.
Include the shared machines in the count. Reception desks, conference room PCs and shop-floor workstations are the devices most likely to carry an old one-time license.
Microsoft 365 Apps or Office LTSC 2024: which upgrade fits your business?
Microsoft 365 Apps fits most businesses, and Microsoft names it as the primary upgrade path. Office LTSC 2024 is the alternative Microsoft offers for organizations that need an on-premises version.
| Option | How you pay | Updates | Supported until | Best fit |
|---|---|---|---|---|
| Microsoft 365 Apps | Per user, per month or year, often already included in Microsoft 365 Business Standard or Premium | Ongoing security and feature updates | As long as the subscription is active | Most businesses, especially teams already on Microsoft 365 email |
| Office LTSC 2024 | One-time volume license | Security updates on a fixed lifecycle | Mainstream support ends October 10, 2029, per Microsoft’s lifecycle page | Machines that must run offline or stay locked to one version, such as equipment control stations |
| Stay on Office 2021 | No new cost | None after October 13, 2026 | Unsupported | Only computers with no internet access and no email |
Check what you already pay for before buying anything. Many businesses carry Microsoft 365 Business Standard or Premium licenses for email and still run a one-time Office 2021 install on some of those same users’ computers. The post on Microsoft 365 licensing explains how to line up licenses with the people who use them.
What to do before October 13
Finish the inventory this week and upgrade the computers that handle email and outside files first. A realistic order:
- Complete the inventory and license match described above.
- Choose a path for each machine: Microsoft 365 Apps for most, Office LTSC 2024 for the exceptions.
- Test the Excel add-ins, accounting integrations and document templates your team depends on in the new version.
- Schedule upgrades outside working hours, starting with front-desk, finance and leadership computers.
- Remove Office 2021 from each upgraded machine so only one version remains.
- Add the next end-of-support dates to your IT roadmap, including Office LTSC 2024 in 2029.
Speed matters even with supported software. The same Verizon report found that organizations took a median of 43 days to fully fix known exploited vulnerabilities in 2026, up from 32 days the year before. After October 13, Office 2021 receives no fix at all. The Windows 10 end-of-support plan follows the same approach for operating systems.
How WEBIT Services handles end-of-support deadlines
WEBIT Services tracks software versions on every managed device through Security Essentials. Security Essentials is WEBIT’s baseline security package that puts Zero Trust EDR, application allowlisting, DNS filtering and vulnerability management on every workstation and server. That inventory is what turns a Microsoft deadline into a list of named computers and a schedule.
Microsoft 365 administration is included in every WEBIT managed IT agreement. If you are unsure how many of your computers still run Office 2021, talk to an owner and we will help you find out before October 13.
