MC1483844 - Microsoft Copilot: GPT 6.1 Sol and Claude Sonnet 5.5 beginning to roll out today

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Metadata at Sep 30, 2026

Message ID

MC1483844

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Published

Sep 30, 2026

Service

Microsoft 365 apps

Tag

New feature

User impact

Admin impact

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What and Why:

To give users more choice and flexibility when working with AI in Microsoft Copilot, we're expanding the set of AI models available in Microsoft Copilot.

Starting today, GPT-6.1 Sol and Claude Sonnet 5.5 begin rolling out today with usage-based billing in Cowork and Microsoft Copilot Studio.

GPT-6.1 Sol and Claude Sonnet 5.5 will also begin rolling out in phases across Word, Excel, PowerPoint, and Chat in the coming week as part of the Microsoft 365 Copilot user subscription license (USL). Limits apply to these models, but they are designed to support broad day-to-day AI usage across organizations and are implemented in such a way that the vast majority of users are not expected to reach them. Users approaching a limit will receive in-product notifications and can continue their work by switching to Auto mode or selecting another available model.

Rollout Schedule:

General Availability:
Cowork and Copilot Studio: Rollout begins today, September 30, 2026.
Word, Excel, PowerPoint and Chat: Phased rollout begins in the coming week.

Impact on Your Organization:

Who is affected:

Cowork and Copilot Studio: Users assigned a user subscription license (USL) with usage-based billing (UBB) enabled.
Word, Excel, PowerPoint, and Chat: Users assigned a user subscription license (USL).
Access to Claude Sonnet 5.5 additionally requires the Anthropic subprocessor to be enabled in your organization.
Access to GPT-6.1 Sol additionally requires the OpenAI subprocessor to be enabled in your organization for select surfaces.

Platforms/Services:

(USL) Microsoft 365 Copilot Chat
(USL) Microsoft Word
(USL) Microsoft Excel
(USL) Microsoft PowerPoint
(UBB) Copilot Cowork
(UBB) Microsoft Copilot Studio

What will happen:

Users will be able to select GPT-6.1 Sol and Claude Sonnet 5.5 using the model selector from supported Microsoft Copilot experiences.
The feature is enabled by default for eligible licensed users who meet the applicable configuration requirements.

[Action Required / Recommendations:

No action is required for organizations that want users to access these models.

Recommended actions:

Review whether the Anthropic subprocessor is enabled if you plan to make Claude Sonnet 5.5 available to users.
Review whether the OpenAI subprocessor is enabled if you plan to make GPT-6.1 Sol broadly available to users. If disabled, GPT-6.1 Sol may not be available from all supported Copilot surfaces.
Review your organization's AI usage guidance and communicate model availability to end users.
Inform helpdesk and support teams that users may encounter usage-limit notifications and can continue working using Auto mode or another available model.
Review the announcement blog for additional details: Available today: OpenAI's GPT-6.1 Sol and Claude Sonnet 5.5 in Microsoft Copilot | Microsoft Community Hub.
Update internal user documentation and training materials, as appropriate.

Compliance Considerations:

Consideration	Explanation
Does the change introduce or significantly modify AI/ML or agent capabilities that interact with or provide access to customer data?	GPT-6.1 Sol and Claude Sonnet 5.5 are additional AI models that users can select within Microsoft 365 Copilot experiences to generate responses based on content and context available to the user through Copilot.
Does the change provide end users any new way of interacting with generative AI?	Users gain access to new model choices, GPT-6.1 Sol and Claude Sonnet 5.5, in supported Microsoft 365 Copilot experiences.
Does the change include an admin control and can it be controlled through Entra ID group membership?	Access to Claude Sonnet 5.5 depends on administrative configuration of the Anthropic subprocessor.