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

Microsoft 365 Message Center announcement MC1483844.

MS Message Center's Summary

Microsoft is rolling out new AI models named GPT 6.1 Sol and Claude Sonnet 5.5 across several Copilot services starting late September 2026. Administrators must ensure that the relevant OpenAI and Anthropic subprocessors are enabled if they want their users to access these new model choices. While the feature enables by default for eligible licences, support teams should prepare for user queries regarding usage limits and switching modes.

Administrator impact
Administrators must review subprocessor settings for OpenAI and Anthropic to enable access to the respective new models.
End user impact
Users gain the ability to select new AI models within supported Microsoft Copilot surfaces subject to usage limits.
Importance
6/10: The introduction of new external AI models requires administrative awareness of subprocessor configurations and user support readiness.

Available today: OpenAI's GPT 6.1 Sol and Claude Sonnet 5.5 in Microsoft Copilot

Microsoft Summary

Microsoft Copilot is rolling out GPT-6.1 Sol and Claude Sonnet 5.5 AI models starting September 30, 2026, across Cowork, Copilot Studio, Word, Excel, PowerPoint, and Chat. Access requires enabling Anthropic and OpenAI subprocessors. Usage limits apply, with notifications and fallback options available. No action needed to enable.

Message Center ID
MC1483844
Category
plan For Change
Severity
normal
Services
Microsoft 365 apps, Microsoft Copilot (Microsoft 365)
Tags
New feature, User impact, Admin impact
Published
2026-09-30
Last updated
2026-10-01
Expires
2027-01-25

[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 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.