Office 2021 End of Life: Support Ended Oct 13, 2026, Yet Microsoft Listed Fixes for 177 Office 2021 Flaws in November

Office 2021 end of life was October 13, 2026, for every edition: retail Office 2021, Office LTSC 2021, the Mac versions, Project and Visio. There is no extended support. Yet 31 days later, as of November 13, 2026, Microsoft had shipped November 10 builds for Windows and Mac and listed fixes for 177 flaws affecting Office LTSC 2021, after 843 in its five-year life.

Key findings

1. All 13 Office 2021 product pages we retrieved from Microsoft’s lifecycle site, from Office 2021 and Office LTSC 2021 to Word 2021 and Skype for Business LTSC 2021, end on October 13, 2026. None has an extended phase.
2. On November 10, 2026, Microsoft’s update history lists a new retail Office 2021 build (Version 2610, Build 20527.20196) and a new Office LTSC 2021 build (Build 14334.21048), the first Patch Tuesday after end of support.
3. Microsoft’s November 2026 security data lists Office LTSC 2021 as affected by 177 CVEs, with fixed builds named for 172 on Windows and 141 on Mac. Office 2019 and Office 2016 are not listed at all that month.
4. Microsoft listed 843 CVEs affecting Office LTSC 2021 from October 2021 to October 2026; 530 of them (63%) came in January to October 2026.
5. 9 of those CVEs are in CISA’s Known Exploited Vulnerabilities catalog. A tenth, CVE-2026-124194 in Outlook, was added on November 10, 2026, after end of support, and Microsoft’s data names a fixed Office LTSC 2021 build for it.
6. Mac owners: Microsoft’s Mac release notes for 16.114.3 (Oct 27) and 16.114.4 (Nov 4) say a previous update “inadvertently disabled Office 2021 for existing users.”
7. Retail Office 2021 runs on the same build as Office 2024 and Microsoft 365’s Current Channel: in 60 of the 62 security releases that list it, the build number matches Current Channel exactly.

Is Office 2021 end of life? Every edition and its date

Yes. Microsoft’s end-of-support page says support “ended on October 13, 2026 and there will be no extension and no extended security updates.” The date is the same for every edition, but the policy behind it differs. Retail Office 2021 follows the Modern Lifecycle Policy with a single retirement date. Office LTSC 2021 follows the Fixed Lifecycle Policy with five years of mainstream support and nothing after it. That gave Office 2021 1,834 days of support from Oct 5, 2021, against 2,577 for Office 2019 and 3,675 for Office 2016, whose story is in our Office 2019 end of life report.

A small trap for anyone reading trackers: every Office 2021 lifecycle page stores the end as 06:59:59 UTC on October 14, 2026, which is October 13 in Redmond. That is why Google’s snippet of the lifecycle page reads “Oct 14, 2026”, while Microsoft’s support pages and endoflife.date say October 13.

Microsoft’s Office LTSC 2021 lifecycle page names the editions “Standard, Standard for Mac”; its LTSC 2021 overview lists Office LTSC Professional Plus 2021 and Office LTSC Standard 2021 for Windows and Office LTSC Standard for Mac 2021 as the volume products. There is no separate “Office 2021 for Mac” lifecycle page: the Mac Home editions sit on the Office 2021 page.

What happened after October 13, 2026

Microsoft’s support page says “you’ll no longer receive Office 2021 software updates.” The first month did not look like that. Microsoft’s Office 2021 update history lists one retail build and one volume build dated November 10, 2026, and its Office security release notes for that day still carry lines for “Office 2021 Retail” and “Office LTSC 2021 Volume Licensed”. The notes cover Office 2019’s post-deadline builds with a written clause (“at Microsoft’s sole discretion, we may choose to issue one or more updates”); they carry no such clause for Office 2021.

Each dot is a release in Microsoft’s Office 2021 update history (Windows) or the Office for Mac release notes, September 1 to November 13, 2026. Larger dots fall after end of support; red Mac dots are the two releases that fix the update that disabled Office 2021.

Two Microsoft pages disagree about end-of-support day itself. The update history gives retail Office 2021 on October 13, 2026 as Version 2609 (Build 20430.20182), the same build as Office 2024. The security notes for that day give Office 2021 retail Version 2608 (Build 20326.20232), a build the update history does not list at all. By November 10 both pages agree on Build 20527.20196, identical to Office 2024 retail and Current Channel. If File, Account shows either October build, update.

Mac: an update that switched Office 2021 off

Microsoft’s Office for Mac release notes “also apply to Office LTSC 2021 and 2024 and Office 2021 and 2024.” Six Mac releases followed the deadline: 16.114 on October 14 (with 93 CVEs listed), three point releases, and 16.115 on November 10 with 140. Versions 16.114.3 and 16.114.4 carry the same line: “A previous update inadvertently disabled Office 2021 for existing users. This update resolves the issue and fully restores functionality for affected customers.” Microsoft does not say which update caused it. The notes also say updates now need macOS 14 (Sonoma) or later. Separately, Microsoft’s Mac update article says Office 2021 on macOS needed version 16.83 or later after July 13, 2026, or it could only “open, view, or print.”

How many Office 2021 security flaws has Microsoft listed?

Microsoft’s Security Update Guide data (the MSRC CVRF API) does not name retail Office 2021 as a product. It names “Microsoft Office LTSC 2021” for 32-bit and 64-bit Windows and “Microsoft Office LTSC for Mac 2021”. Counting every CVE where either is a known affected product, Microsoft listed 843 from October 2021 through October 2026: 785 on Windows and 609 on Mac. Retail Office 2021 receives the same fixes through its shared build, so the count is the best public measure for both.

The count did not rise evenly. Office LTSC 2021 drew 136 CVEs in the 12 months to October 2025 and 554 in the 12 months to October 2026, 4.1 times as many, with the jump from July 2026 onward. That tracks the Microsoft-wide surge in our Patch Tuesday statistics for 2026, and it means Office 2021 left support at the moment Microsoft was disclosing Office flaws fastest: 165 in October 2026 alone.

Unique CVE IDs per calendar year in MSRC monthly documents. Builds: release rows in Microsoft’s Office 2021 update history, which lists retail releases from October 6, 2021 and volume releases from October 12, 2021.

Retail Office 2021 updates on the Current Channel cadence, several times a month; Office LTSC 2021 updates roughly once a month, mostly on Patch Tuesday.

Exploited flaws: the CISA list

CISA’s Known Exploited Vulnerabilities catalog (version 2026.11.10) contains 9 CVEs that Microsoft lists for Office LTSC 2021 during its supported life, and one more after it. Microsoft’s own data flagged 8 Office LTSC 2021 CVEs as already exploited at release. The most recent, CVE-2026-124194 in Outlook, entered the catalog on November 10, 2026, the same day Microsoft named Office LTSC 2021 Build 14334.21048 and Mac 16.115 as its fix. Our CISA KEV analysis for 2026 covers the catalog as a whole.

What still works, by edition

The connectivity line is the one most likely to bite a business. Microsoft’s Microsoft 365 connectivity table now lists only Microsoft 365 Apps and Office LTSC 2024 (to October 9, 2029) as current, with Office LTSC 2021 at October 13, 2026. Older versions “might still be able to connect”, Microsoft says, but service changes are no longer tested against them.

Upgrade options and what they cost

There is no discounted path. Microsoft’s upgrade page says owners of a one-time purchase “need to buy the latest version”. The replacements, with Microsoft US list prices retrieved Nov 13, 2026: Office Home 2024 at $179.99 (non-commercial use, no Outlook), Office Home & Business 2024 at $249.99, Microsoft 365 Personal at $99.99 a year ($69.99 first-year offer at retrieval), Family at $129.99 a year, and for business Business Basic at $7.00, Apps for business at $10.00 ($12.00 month to month) and Business Standard at $14.00 ($16.80) per user a month. The one-time 2024 products end on Oct 9, 2029, 1,061 days (2.9 years) from today; Office LTSC 2024 is sold only through volume licensing, has no public price, and ends the same day.

One more date belongs in the plan: Office 2024 gets five years where Office 2021 got five, Office 2019 about seven and Office 2016 ten. Anyone buying a one-time license now is buying 2.9 years of support, which our Microsoft end of support 2026 calendar puts alongside the rest of this year’s deadlines.

What this means for MSPs

• Report Office 2021 as unsupported, even where it patched in November. The November 10 builds came with no written commitment, unlike the “sole discretion” clause Microsoft published for Office 2019. Put the seat count and October 13, 2026 in each client’s lifecycle report.
• Push the November builds anyway. Build 14334.21048 (LTSC) and 20527.20196 (retail) carry fixes for 177 CVEs Microsoft lists for Office LTSC 2021, including CVE-2026-124194, in CISA’s catalog since November 10.
• Check Mac fleets for 16.114.3 or later. Earlier October builds may have left Office 2021 disabled; Microsoft says 16.114.3 and 16.114.4 restore it. Macs below macOS 14 no longer receive updates at all.
• Flag Office LTSC 2021 Outlook on Exchange Online. That pairing lost connectivity support on October 13, 2026, and it is the first thing a Microsoft 365 service change will break.
• Price per seat over the real term. For 25 seats over three years, Business Standard lists at $12,600.00, Apps for business at $9,000.00, and Office Home & Business 2024 at $6,249.75 once, with support ending Oct 9, 2029.

Frequently asked questions

When is Office 2021 end of life?

October 13, 2026, for every Office 2021 edition: Home & Student, Home & Business, Professional, the Office LTSC 2021 volume editions, the Mac versions, Project, Visio and the single apps. Microsoft’s lifecycle pages store the time as 06:59 UTC on October 14, which is why Google and some trackers show October 14.

Is there extended support for Office 2021 or Office LTSC 2021?

No. Microsoft’s end-of-support page says there will be “no extension and no extended security updates.” Retail Office 2021 follows the Modern Lifecycle Policy with a single retirement date, and Office LTSC 2021 has five years of mainstream support with no extended phase.

Does Office 2021 still work after end of life?

Yes. Microsoft says the apps “may continue to function.” On Nov 10, 2026, 28 days after the deadline, Microsoft still shipped Office 2021 builds for Windows (retail Build 20527.20196, volume Build 14334.21048) and Mac (16.115). Microsoft has made no promise of more.

Is Office 2021 still getting security updates?

Not officially. Microsoft says it will no longer provide security fixes, yet its November 10, 2026 security data lists Office LTSC 2021 as affected by 177 CVEs, with fixed builds named for 172 on Windows and 141 on Mac. Unlike Office 2019, there is no written “sole discretion” clause for Office 2021, so each month is a surprise.

Is Office 2021 for Mac end of life too?

Yes, on the same day, October 13, 2026. Mac buyers had a second problem: Microsoft’s Mac release notes for versions 16.114.3 (October 27) and 16.114.4 (November 4) say a previous update “inadvertently disabled Office 2021 for existing users” and that the fix restores it. Updates also require macOS 14 or later.

Can I upgrade Office 2021 to Office 2024 for free?

No. Microsoft’s upgrade page says owners of a one-time purchase “need to buy the latest version.” Office Home 2024 lists at $179.99 and Office Home & Business 2024 at $249.99 in Microsoft’s US store; both are supported until October 9, 2029.

Free to cite and republish with a link. The CSV holds the 13 Office 2021 lifecycle rows and 62 monthly rows (October 2021 to November 2026) with CVE counts for Office LTSC 2021 and build counts.

References

1. Microsoft Lifecycle, Office 2021, Office LTSC 2021, Office LTSC 2021 for Mac, and the other Office 2021 family pages linked in the edition table. Accessed November 2026.
2. Microsoft Lifecycle, Office 2024 and Office LTSC 2024. Accessed November 2026.
3. Microsoft, Modern Lifecycle Policy and Fixed Lifecycle Policy. Accessed November 2026.
4. Microsoft Support, End of support for Office 2021. Accessed November 2026.
5. Microsoft Learn, Update history for Office LTSC 2021 and Office 2021. Accessed November 2026.
6. Microsoft Learn, Release notes for Microsoft Office security updates. Accessed November 2026.
7. Microsoft Learn, Release notes for Office for Mac. Accessed November 2026.
8. Microsoft Support, Update Microsoft 365 or Office on your macOS or iOS device. Accessed November 2026.
9. Microsoft Learn, Overview of Office LTSC 2021 and Overview of Office LTSC 2024. Accessed November 2026.
10. Microsoft Learn, Office versions and connectivity to Microsoft 365 services. Accessed November 2026.
11. Microsoft Learn, Plan an upgrade from older versions of Office to Microsoft 365 Apps and Office and Windows configuration support matrix. Accessed November 2026.
12. Microsoft Security Response Center, CVRF API v3.0. Accessed November 2026.
13. CISA, Known Exploited Vulnerabilities Catalog. Accessed November 2026.
14. Microsoft Support, How do I upgrade Office? and Download and install or reinstall Office 2021, Office 2019, or Office 2016. Accessed November 2026.
15. Microsoft US store and plan pages: Office Home 2024, Office Home & Business 2024, Microsoft 365 Personal, Microsoft 365 Family, Business Basic, Apps for business, Business Standard. Accessed November 2026.
16. endoflife.date, Microsoft Office. Accessed November 2026.