October 2026 is the worst month Office users have had in years
October is a big month for Microsoft 365 and Microsoft Office customers but not in a good way. There are many changes happening in October 2026 including an important app and some features that will stop working completely, one version of Office loses support and some Microsoft 365 customer stop getting new features.
To paraphrase a great poet “October is the cruelest month”, at least for Microsoft’s paying customers.
Most of the changes land on Tuesday October 13, 2026, which is Patch Tuesday. But the two items most likely to actually hurt you happen twelve days earlier, on October 1. One of them is a genuine kill switch.
Here is the full list, in date order, with what to do about each.
October 1: Publisher stops working for Microsoft 365 subscribers
This is the only item on the list that is a kill switch, not just an end of security patches.
Microsoft’s support page says Microsoft 365 subscribers will not be able to access Publisher after October 1, 2026. Translation: Publisher 365 will stop working completely.
You will not be able to open or edit Publisher files in Publisher 365, and the app disappears from the install and download options. The app does not limp on unsupported. It goes away.
See Microsoft Publisher Ends October 2026: How to Keep It Working
Publisher’s .pub format is proprietary and nothing else reads it reliably. Convert your .pub files to PDF or Word before October 1.
Watch out: plenty of coverage quotes October 13 for Publisher. That date applies only to the perpetual license version, see below. If you are on a Microsoft 365 subscription, October 1 is the end date
October 1: Exchange Web Services blocked in Exchange Online
Not an app, but it will break things. Any tenant with EWSEnabled still set to Null on October 1, 2026 will have that value flipped to False as the rollout proceeds, which blocks Exchange Web Services for every application in the tenant. The full permanent shutdown follows on April 1, 2027, with no exceptions.
This is Exchange Online only. EWS in on premises Exchange Server is untouched. Outlook, Teams and other Microsoft apps do not use it. What breaks is older third party software: backup tools, archiving products, CRM plugins, email signature managers and migration tools.
What to do: check EWSEnabled in your tenant now and pull the EWS usage report. Of everything in this article, this is the change most likely to generate support tickets nobody saw coming.
October 5: Teams live chat closes
Microsoft is shutting down the Teams live chat widget on October 5, 2026, roughly 18 months after launching it. New setups have been blocked since August 6, 2026.
After the cutoff the widget stops relaying customer messages from your website into Teams. Historical chat content already stored in the Teams channel stays put and is not deleted. Any widget still sitting on a website after October 5 simply becomes hidden.
What to do: find the tag with id=”chatbot” on your web pages and remove it before October 5. Microsoft is pointing replacements toward Dynamics 365 Contact Center or Copilot Studio, both of which are considerably more product than a small business asked for.
Sometime in October: Teams calendar sync with Google Workspace ends
Microsoft has not committed to a day for this one, which is itself worth knowing. MC1462469 lists the retirement as simply “October 2026” and puts an “Act by” date of October 1, 2026 on the admin tasks.
When it happens, calendars that were previously matched and configured will stop syncing, and administrators lose access to the calendar sync setup inside the Admin app in Teams. The Admin app itself is being retired in the same month, so the settings screen may well vanish before the sync does.
What to do by October 1: open the Admin app in Teams and retrieve your account matching information while you still can. For people who need to schedule Teams meetings from Google Calendar afterward, the supported path is the Microsoft Teams Meeting add on for Google Workspace, which is one way scheduling rather than two way sync. That is a downgrade, not a replacement, and it is worth telling your users so plainly.
October 13: the entire Office 2021 family
Support ends October 13, 2026 for all Office 2021 products, including the LTSC variants.
Retail and subscription style products retiring
- Office 2021 (the suite)
- Word 2021, Excel 2021, PowerPoint 2021, Outlook 2021, OneNote 2021, Access 2021
- Publisher 2021
- Project 2021
- Visio 2021
Volume license and perpetual products, same day
- Office LTSC 2021 and Office LTSC 2021 for Mac
- Word LTSC 2021, Excel LTSC 2021, PowerPoint LTSC 2021, Outlook LTSC 2021, OneNote LTSC 2021, Access LTSC 2021
- Publisher LTSC 2021
- Project 2021 (LTSC)
- Visio LTSC 2021
- Skype for Business LTSC 2021
The apps keep working. What stops is technical support, bug fixes and security fixes. Microsoft Update stops delivering Office 2021 updates, and phone and chat support ends. Any security flaw found after that date is permanent.
However, Office 2019 Is Still Getting Security Updates, But Only for Some so it’s possible a similar thing will happen for some Office 2021 customers. We’ll have to wait for later Patch Tuesday updates to see what Microsoft does.
See our guide to Office 2021 alternatives including ones that Microsoft doesn’t mention.
October 13: the Microsoft 365 feature freeze on Windows 10 spreads
If you run Microsoft 365 Apps on Windows 10, your new features have already stopped or are about to, depending on your update channel. Version 2608 reached Current Channel in August 2026, reaches Monthly Enterprise Channel on October 13, 2026, and reaches Semi Annual Enterprise Channel on January 12, 2027.
Microsoft 365 apps on Windows 10 will sit on Version 2608 and get security updates only, until October 10, 2028. See Windows 10 Users: Microsoft 365 Just Stopped Getting New Features
This is not an app dying. It is Word, Excel, Outlook and the rest becoming a fixed feature set on Windows 10. New features and ribbon changes go to Microsoft 365 on Windows 11 only.
October 13: Microsoft 365 Apps on Windows Server 2022
It’s a similar story for Microsoft 365 apps on Windows Server 2022. Microsoft will keep issuing security updates for the desktop apps on Server 2022 until October 10, 2028, and those machines freeze at Version 2608 as well.
This bites anyone running Office on Remote Desktop Session Hosts or Citrix on Server 2022, which is a lot of small and medium businesses who do not think of themselves as running a server product.
Also on October 13, not Office but same day
- Windows 11 version 24H2 reaches end of servicing for Home and Pro. Enterprise and Education stay supported until October 12, 2027.
- Windows Server 2022 moves from mainstream to extended support.
What software is affected in October 2026
Publisher on a Microsoft 365 subscription
This is urgent because Publisher 365 will stop working completely, not just end support. Check out our guide to your options for keeping Publisher alive or at least maintaining access to your.pub files.
Office 2021
Nothing breaks on October 14. Your files still open, your software still runz. But there is no paid safety net this time, so treat it as a security decision rather than a deadline.
Microsoft’s recommended paths are Microsoft 365 Apps, or Office 2024 but there are other choices.
Windows 10 with Microsoft 365
Your Microsoft 365 apps are safe and supported until October 2028 (??? Date code) but no new or changed features after version 2608.
Keep using Windows 10, especially if you have the ESU option but don’t get excited when you read about something new in the Microsoft 365 apps because that’s limited to Windows 11.
If you are the admin
Three things, in this order. Check EWSEnabled in Exchange Online and pull the EWS usage report. Save your Google Workspace account matching data out of the Teams Admin app. Strip the chatbot widget tag off your website. All three are October 1 to October 5 work, and none of them will remind you.