Wednesday, 23 September 2026

Word document summarization moves off Top of Doc

The Top of Doc summarization experience in Microsoft Word is being retired and its summaries move to other Copilot in Word surfaces: a proactive "Summarize this document" suggestion, and natural language prompts in Copilot. MC1454113, updated September 21 to clarify the timeline; GA rollout began early September 2026 across Worldwide, GCC, GCC High and DoD, and no admin action is required.

Why it matters: The capability survives but the entry point does not, so adoption material and help desk documentation referencing Top of Doc need rewriting before users report summarization as missing.

mc.merill.net

Copilot web app redirects to copilot.cloud.microsoft

Microsoft began redirecting users from m365.cloud.microsoft to copilot.cloud.microsoft in early September for tenants that already allow the domain, and will redirect the remaining users in early October 2026. MC1462915, updated September 21; devices, proxies, firewalls or security gateways blocking any URL under *.cloud.microsoft will break Copilot in the web app, the desktop app and Microsoft Edge, and connectivity can be checked with the Microsoft 365 Connectivity Test tool.

Why it matters: This is a network allow-list change with a hard October deadline, and tenants that miss it lose Copilot access outright rather than degrading gracefully.

mc.merill.net

Local inferencing

Local inferencing expands Microsoft Copilot’s sovereign controls by enabling AI inferencing for supported Copilot interactions to occur within the applicable local geography.

mc.merill.net

Reference files saved in SharePoint libraries and OneDrive folders when creating a presentation with Agent Mode in PowerPoint

You can now reference files saved in SharePoint libraries and OneDrive folders when creating a presentation with Agent Mode in PowerPoint.

mc.merill.net

Claude Opus 5.5 and GPT-6 Sol roll out across Microsoft Copilot

Anthropic's Claude Opus 5.5 and OpenAI's GPT-6 Sol began rolling out to Microsoft Copilot across Word, Excel, PowerPoint, Chat, Cowork and Copilot Studio, with Work IQ grounding responses in the organization's files, meetings, chats and business data. Microsoft states availability may vary by license, access and region, and points to the AI at Work Roadmap and the Microsoft 365 Copilot release notes for rollout status.

Why it matters: Two frontier models land in the same picker on the same day, so model guidance and any per-tenant availability promise need re-checking before the next customer conversation.

techcommunity.microsoft.com

Microsoft OneNote: Copilot notebook available in OneNote on Mac

Copilot Notebook, a new AI-powered workspace in OneNote on Mac, helps users organize and analyze notes using Microsoft 365 Copilot. It requires a Copilot license, is enabled by default, and will roll out worldwide from late August to mid-October 2026. No admin action is needed.

mc.merill.net

GPT-6 Astra, Sol and Luna reach GA in Microsoft Foundry

All three GPT-6 models are generally available in Microsoft Foundry: Astra for work needing judgment and action including software engineering and computer use, Sol as the general-purpose production model, and Luna for high-volume extraction, summarization and routine interactions. Standard deployment covers 28 Global regions plus the US and EU Data Zones for all three; Provisioned Throughput covers Astra and Sol across Global regions and the US and EU Data Zones; Priority Processing covers Sol across Global regions and the US Data Zone only.

Why it matters: The EU Data Zone carries standard and provisioned deployments but not Priority Processing, and that split is what decides which serving option an EU or Swiss customer can actually use.

azure.microsoft.com

Claude Opus 5.5 available in Microsoft Foundry

Anthropic's most capable Opus model is available in Microsoft Foundry for developers and enterprises building AI applications and agents, aimed at long-running coding, investigation and knowledge work across large codebases and long documents. Microsoft cites lower per-token prices and cheaper cache reads than Opus 5, plus agentic communication improvements that surface what the model did, what it found and what it needs next.

Why it matters: Long-running agent sessions are where token cost compounds, so a cheaper Opus tier changes the economics of agent workloads already sized on Opus 5.

techcommunity.microsoft.com

User and session isolation for Foundry hosted agents

Foundry hosted agents gain two isolation controls surfaced through Microsoft Agent Framework: user isolation, which decides whose data an agent may use based on the caller's Microsoft Entra identity or a delegated identity from a trusted middle tier, and session isolation, which keeps code and files in VM-isolated sandboxes keyed by agent_session_id. Foundry hosted agents are GA, but the AgentServer SDKs and the Agent Framework Foundry hosting packages for .NET and Python remain pre-release.

Why it matters: A multi-tenant agent deployment needs both controls to be defensible, and the pre-release SDK status means the contract can still shift before a production rollout.

devblogs.microsoft.com

Microsoft Teams: Removing Copilot from the chat list

Starting October 2026, Microsoft Teams will remove the Copilot chat list entry point, directing users to access Copilot solely through the Copilot app in the Teams app bar for a streamlined experience. Mobile users are unaffected, and no data will be lost. No action is required.

mc.merill.net

Customized Viva Insights Power BI reports stay on their original version

Customized Viva Insights Power BI reports stay tied to the report version they were created from and are no longer migrated automatically when a major out-of-the-box report update ships. MC1476322, available now; older versions may stop receiving refreshed data and users see "A newer version of this report is available", so anyone needing current data must build a new customized copy from the latest report version. No admin configuration and no tenant setting changes.

Why it matters: A customized adoption or Copilot report goes quietly stale instead of breaking, so report owners need a recurring check that their copy still sits on a supported version.

mc.merill.net

Microsoft Purview | Data Lifecycle Management: Retention based on “last accessed” for OneDrive and SharePoint files

Admins can apply retention policies in OneDrive and SharePoint to delete Office files based on their last accessed date, starting preview in late November 2026 and general availability in January 2027. This improves data relevance for Microsoft 365 Copilot. No admin action is needed before rollout.

mc.merill.net

Teams message remediation from the Defender entity flyout

Security admins investigating Teams messages through Submissions, Alerts, Advanced Hunting or Quarantine can open the Teams message entity flyout and run a Take action wizard that submits the message to Microsoft, blocks the external sender and blocks associated domains in the Tenant Allow/Block List, with sender and domain details prepopulated and several actions allowed in one pass. MC1476237, GA Worldwide from late September 2026 completing mid-October, for Defender for Office 365 Plan 1 and Plan 2, with no configuration change required.

Why it matters: Teams phishing response collapses from several portals into one workflow, which is the difference between a runbook that gets followed and one that gets improvised.

mc.merill.net

MessageContents table in Advanced Hunting for Teams messages

A new MessageContents table in Microsoft Defender XDR Advanced Hunting exposes Teams message snippets and related metadata so analysts can correlate Teams activity with other security signals. MC1474106, GA Worldwide from late September 2026 completing mid-October; the table can contain message content, so access is permission controlled and needs both Advanced Hunting and message preview permissions, and it currently covers messages available through the Teams message metadata source, including messages carrying URLs and federated messages.

Why it matters: Teams message bodies become queryable in hunting, which is a real investigative gain and a real data-access question for works councils and privacy reviews in EU tenants.

mc.merill.net

Skills in Brand Kit

Upload skill (.md file) in Brand Kit and use within PPT Copilot

mc.merill.net

Clinical Applications specialization for Dragon Copilot

From September 30 2026 eligible partners can earn a new specialization for deploying Dragon Copilot in healthcare, unlocking co-sell and referral eligibility, funding, Azure bulk credits, deployment support and go-to-market assets.

learn.microsoft.com

Microsoft Ignite session catalog is live

The session catalog and registration opened for Microsoft Ignite, running in person and online November 17-20 2026.

learn.microsoft.com

Prepare your tenant estate for AI: upcoming webinars

Microsoft Entra webinar series on multi-tenant visibility, consistent policy and shadow-tenant risk, following the GA of Microsoft Entra Tenant Governance.

techcommunity.microsoft.com

Demystifying dynamic AI routing with the Foundry model router and RouteLab

Walkthrough of the Foundry Models model router's Balanced, Cost and Quality routing modes, evaluated locally with the RouteLab playground.

techcommunity.microsoft.com