SharePoint Online Weekly Update — September 7, 2026

Copilot in SharePoint Makes Skills Portable and Teaches Agents to Build SharePoint-Safe

The headline for the week is the September 2026 "What's New in Copilot in SharePoint" update, and its most important idea is portability. Reusable skills — your preferred formats, standards, and repeatable ways of working — can now follow you across SharePoint and OneDrive instead of being trapped on a single site. You define a skill once and it travels with you, and Copilot can measure and improve those skills with evaluations, so a skill is no longer a static prompt but something you can benchmark and refine over time. SharePoint Site Skills layers on the governance that makes this safe at scale, adding versioning and cross-site reuse so an organization can curate approved skills rather than watch every team reinvent them.

The second half of the announcement is quieter but arguably more strategic: Microsoft has published guidance that points AI assistants at up-to-date instructions for generating HTML that actually works inside SharePoint's sandbox, including support for capabilities like live-linked SharePoint lists. Any general-purpose assistant — Cowork, Scout, GitHub Copilot, Copilot Studio — tends to emit standard web HTML that breaks or renders wrong once dropped into SharePoint. This guidance closes that gap and updates automatically as new capabilities light up in your tenant, so you stop having to explain SharePoint's constraints to the model by hand.

This is exactly the terrain where shaping AI deliberately pays off. A portable, evaluated skill built on a clean standard becomes a reusable organizational asset; an unmanaged skill copied between sites becomes drift you cannot audit. The teams that win here are the ones treating skills as governed artifacts — named owners, versions, and evaluation criteria — from day one, rather than discovering after the fact that fifty slightly different versions of "summarize this site" are floating around the tenant.

What to do: Nominate one or two high-value reusable skills your teams already do by hand, define them once, and stand up an approval and versioning process in SharePoint Site Skills before informal skills proliferate — then point your build tooling at Microsoft's new SharePoint-safe HTML guidance so AI-generated components render correctly the first time.

The New SharePoint Experience Finishes Its No-Opt-Out Rollout This Month

The new SharePoint experience — the redesigned app bar with Discover, Publish, and Build hubs, the refreshed start page, and the rename of Followed Sites and Saved for Later to Favorites — is completing its general availability rollout across tenants this month. The important detail for admins is that this is not opt-in. Beginning with the Targeted Release wave, the new experience applied automatically to all tenants and users, overriding any tenant-level preview settings or individual opt-outs, and no controls remain to hold it back.

For most users the change is a navigation refresh, but the AI-assisted capabilities surfaced through the new app bar generally require a Copilot license, which means your users will see entry points to features they may or may not be entitled to. That mismatch between what the interface promises and what a given license actually unlocks is a predictable source of help-desk tickets, and it is worth getting ahead of with a short internal note rather than fielding the confusion one ticket at a time.

Because there is no opt-out, the only real lever left is communication and documentation. Any internal training, screenshots, or intranet guidance that still shows the old app bar is now wrong, and users who navigated by muscle memory will need a moment to relearn where Publish and Build live.

What to do: Send a brief change note to end users showing the new app bar and where Favorites, Discover, Publish, and Build now live, clarify which AI features require a Copilot license, and refresh any intranet documentation or training that still pictures the previous navigation.

SPFx 1.24 Reaches General Availability — With a Hard Heft Deadline

For developers, SharePoint Framework 1.24 hits general availability this month, and it is a consequential release. It carries SharePoint Copilot Apps to general availability, ships the SPFx CLI as GA, adds navigation customizers and refreshed open-source templates, and continues the npm dependency-security work — all on top of the React 18 support confirmed during the beta cycle. Notably, Microsoft swapped the September release from the expected 1.25 back to 1.24 to get these AI-focused capabilities into customers' hands sooner.

The catch is the build-toolchain change riding along with it. SPFx 1.24 moves the build system toward Heft, and Microsoft is explicitly urging teams to migrate critical Gulp-based projects to Heft ahead of this release. Custom web parts and extensions built on the older Gulp pipeline are the ones at risk, and "critical" here means anything your business actually depends on in production. A toolchain migration is rarely a one-afternoon job, so treating this as a routine version bump is how a working solution quietly stops building.

The Copilot Apps GA is the strategic half of this release. It moves AI-driven SharePoint experiences out of preview and into something you can deploy with support, but a Copilot App is only as trustworthy as the business process underneath it. An app built against a clean, well-modeled list is a durable asset; one built against an undocumented workflow is technical debt wearing an AI label.

What to do: Have your development team inventory custom web parts and extensions still on the Gulp pipeline and schedule the Heft migration for anything business-critical now, validate existing solutions against SPFx 1.24 and React 18 in a non-production tenant, and identify one clean business process to ship as a supported Copilot App rather than bolting AI onto a messy one.

Storage Billing and File Archiving Change the Admin Math

Two administrative changes arriving this month reshape how organizations manage SharePoint capacity and retention. First, pay-as-you-go billing for extra Microsoft SharePoint storage is coming, giving admins a metered option for capacity that exceeds the tenant's pooled allocation instead of buying storage in fixed add-on blocks. That is a genuine flexibility win for tenants that periodically spike over their quota, but metered billing also means storage sprawl now has a direct, recurring line-item cost — the incentive to clean up stale content just got a dollar figure attached.

Second, file archiving support in SharePoint Online lets administrators fold archiving actions into existing data retention policies, moving cold content to a lower-cost tier while keeping it discoverable and governed. Combined with pay-as-you-go pricing, archiving becomes the natural pressure-release valve: rather than paying metered rates to keep rarely touched files on primary storage, you can age them into the archive tier under the same lifecycle rules you already run.

The two features are best understood as a pair. Metered storage creates the cost signal, and archiving gives you the mechanism to respond to it. Organizations that have deferred content lifecycle work because it was nobody's budget problem will find the economics have quietly changed.

What to do: Model your tenant's storage against the new pay-as-you-go rates to understand your exposure, then extend your data retention policies to include archiving actions for cold content — and use the moment to identify the stale sites and libraries that will otherwise cost you metered storage every month.

Sharing Gets a Next-Generation Experience, and Whiteboard Files Change Homes

Collaboration mechanics are shifting on two fronts. Microsoft is rolling out a next generation of the Microsoft 365 sharing experience, designed to make collaboration simpler and more secure by default, anchored by a new hero link that governs how a file is accessed. The intent is to make the most common, most appropriate sharing choice the default one, reducing the accidental over-sharing that happens when users click through a dialog without reading it. As with any change to sharing defaults, the practical risk is that muscle memory betrays users during the transition, so a short refresher on what the new default link actually grants is worth the effort.

Separately, a governance-relevant storage change lands late this month: Teams Channel Whiteboard files will be stored in the channel's associated SharePoint site rather than in the creator's OneDrive. This is a sensible correction — a shared channel artifact belongs with the channel's other shared content, not tied to one person's personal storage where it disappears if they leave — but it does move where those files live for retention, permissions, and discovery purposes. Anything that assumed whiteboards lived in a user's OneDrive needs revisiting.

Taken together, both changes push in the same direction Microsoft has favored all year: collaboration content sitting in governed, shared locations with sensible defaults, rather than in personal stores with permissive ones.

What to do: Brief users on the new hero link default before it changes their sharing habits, and update retention, permissions, and eDiscovery assumptions to account for Teams Channel Whiteboard files now living in the channel's SharePoint site rather than a user's OneDrive.

Retirement Watch: October Cutoffs Are Now Weeks Away

With so much new capability arriving, the retirements still moving through the 2026 calendar are easy to lose track of — and several are hard cutoffs, not soft deprecations. The most urgent remains the SharePoint One-Time Passcode (OTP) external authentication method, which begins its production retirement on October 1, 2026 and completes across environments by month-end, with external sharing moving to Microsoft Entra B2B guest accounts. OTP-based sharing links will start failing at the start of October, so the window to pre-provision B2B guests for the partners you actively work with is now measured in weeks.

Longer-horizon changes are worth keeping on the calendar too. Microsoft is retiring all four standalone SharePoint Online and OneDrive for Business plans — no new sales after May 2026, no renewals after January 2027, full retirement by December 2029 — which affects any organization licensing SharePoint outside of a Microsoft 365 suite. Earlier 2026 retirements, including the SharePoint Add-in model, Azure Access Control Service (ACS), legacy IDCRL authentication, and legacy compliance features in favor of Microsoft Purview, are already past their cutoffs; if anything in your tenant still depends on them, that is an open incident waiting to happen rather than a future planning item.

What to do: Before October 1, audit external sharing for links that still rely on SPO OTP and pre-provision Entra B2B guests for active partners, confirm your SharePoint licensing path if you hold any standalone plans, and verify that reliance on already-retired Add-ins, ACS, or IDCRL has a completed migration rather than an open ticket.

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