This article is mostly in the past tense, which makes it different from the equivalent in the mail baseline. Six things in the collaboration estate stopped working during the first seven months of 2026, and if something broke in your tenant this year and nobody could explain it, the explanation is probably on this page. One thing breaks in October, and it is the only item in this wave that anybody needs to act on. And one door closed behind every tenant in the service without asking.
I have written the dates knowing that a reader may arrive at this a year later, so each one says whether it has landed or not as of writing rather than assuming the present tense holds.
The one that matters: October
SharePoint’s own passcode authentication for external people retires during October, running from the first of the month to the end of it. External people holding links, with no guest account in your directory, lose access when it lands. Anonymous links are unaffected because they never authenticated anybody.
Two things about this date are worth carrying. It moved: it was announced for July and rescheduled in the middle of that month. And Microsoft’s own documentation had not caught up at the time of writing, still saying July on the relevant page while the Message Center post said October. When a vendor’s two surfaces disagree, the announcement is the authority and the documentation lags, which is the general rule and not a criticism.
The work is an inventory rather than a configuration change, it takes real time on a real estate, and the practical deadline is therefore the end of September rather than the first of October. It has its own build sheet in this series and that is the article to read if you read only one.
The door that closed behind you
From May 2026 Microsoft enabled the Entra business-to-business integration for external sharing in every tenant, regardless of what the tenant’s own setting said, and removed the ability to disable it. That is the closest thing this wave has to a one-way door, and it is unusual because you did not walk through it, you were carried.
The consequence is the one the anchor article opens with. Invitation permissions, domain restriction, cross-tenant access and guest session behaviour are Entra concerns now, permanently and unconditionally. Any runbook step that enables the integration is a no-op, and any documentation describing the SharePoint domain list as the control for file sharing is describing a list that no longer decides anything a user experiences.
The other irreversible thing in this estate is not a Microsoft decision, it is yours: an anonymous link with no expiry is a credential in somebody’s mailbox that you cannot recall and cannot enumerate the recipients of. Revoking it means finding it. That is why expiry belongs on every anonymous link even in an estate that permits them freely.
What already stopped working this year
April: the add-in model and the identity service behind it. SharePoint Add-Ins stopped working in SharePoint Online, and Azure Access Control Service for SharePoint Online retired completely with no extensions. On the same date, SharePoint 2013 workflows were removed from tenants that still had them, and domain-isolated framework web parts stopped working. That is four related things on one day, all of them the end of a modernisation programme that had been running for years with repeated extensions. The extensions stopped. If a line-of-business integration died in April and the vendor has been quiet since, this is why.
May: Office 365 connectors in Teams. Disabled during the second half of May, with the migration deadline having passed in March. The replacement is the Workflows app. Anything that posted into a channel from an external system through a connector stopped posting, and the failure is silent from the channel’s point of view, which is why some of these are still undiscovered.
July: InfoPath, twice. Publishing new or updated forms was blocked in May, and the forms service in SharePoint Online retired on the fourteenth of July, at which point existing forms stopped rendering. The same date took SharePoint Server 2016 and 2019, SharePoint Designer 2013 and the InfoPath 2013 client out of support, which is on-premises territory and out of scope here, but the coincidence of dates means an organisation with both is dealing with two problems at once.
July: SharePoint Alerts, and this is the user-visible one. The retirement was staged across a year. No new alerts for new tenants from July 2025, then a rolling thirty-day expiry applied to every existing alert from October, then creation switched off for everybody in January 2026, and from July 2026 the ability to use them removed entirely with no further extension. The staging is why this one produced a trickle of confused tickets rather than a single outage: people’s alerts stopped one at a time as each hit its thirty days. The replacements are SharePoint Rules and Power Automate, and there is a gap worth knowing about, because Site Pages libraries do not support Rules, so anything watching a pages library has to go to Power Automate.
June: Teams Live Events. Retired on the thirtieth of June, with events already scheduled before that date honoured through to the end of February 2027. Town hall and the unified events experience are the replacement. That February date is the last future date in this wave’s calendar and it is the only one that will still be sitting in someone’s diary.
July: Restricted SharePoint Search. New enablement blocked from the thirty-first. Covered in the Copilot readiness article, and the summary is that if you never enabled it the retirement costs you an option you should not have wanted.
A checked absence, stated deliberately
I looked for OneDrive-specific retirements in this window and found none beyond the shared platform items above. That is worth saying rather than leaving as silence, because an absent item in a calendar reads as an oversight and this one is a finding. OneDrive’s exposure in this wave is its sharing defaults and its role as the place sensitive material accumulates, not a dated change.
The calendar, in brief
| When | What | Why it matters to you |
|---|---|---|
| 2 April 2026, landed | SharePoint Add-Ins stop working; Azure Access Control Service for SharePoint Online retires; 2013 workflows removed; domain-isolated web parts stop | Four related failures on one day, after years of extensions. The explanation for an integration that died in April |
| Second half of May 2026, landed | Office 365 connectors in Teams disabled; replacement is the Workflows app | Channel posts from external systems stopped, silently |
| 14 July 2026, landed | InfoPath Forms Services in SharePoint Online retires; forms stop rendering | Any surviving InfoPath form is now a dead page |
| July 2026, landing | SharePoint Alerts removed entirely, after a year of staged expiry | The most user-visible retirement in the wave; Rules and Power Automate replace it, and Site Pages libraries need Power Automate |
| 30 June 2026, landed | Teams Live Events retired | Town hall replaces it; already-scheduled events survive to February |
| 31 July 2026, landed | Restricted SharePoint Search: new enablement blocked | Costs you nothing if you never enabled it; plan the move to restricted content discovery if you did |
| 1 to 31 October 2026 | SharePoint passcode authentication retires; externals without a guest account lose access | The only item requiring action. Inventory complete by end of September |
| 28 February 2027 | Last day for Teams Live Events scheduled before the retirement | The last future date in this wave |
| Closed, no reversal | Entra business-to-business integration force-enabled, disable toggle removed | Sharing governance is an Entra concern permanently; runbook steps that enable it are no-ops |
| Your one-way door | An anonymous link published with no expiry | A credential you cannot recall and whose recipients you cannot enumerate |
The last article in this series is the checklist: every action from all three tiers, with the way to verify it and a pointer to the article that argues for it.
Best Practices
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Next: [BP 3.5] The Collaboration Quick Checklist ›
