Microsoft 365 Copilot: Claude Sonnet 4.5 retiring for Copilot Studio (automatic migration to Claude Sonnet 4.6) [MC1296875]

Message ID: MC1296875

[Introduction]

Starting May 30, Microsoft Copilot Studio agents that are currently configured to use Claude Sonnet 4.5 will be automatically migrated to newer, supported models. This migration aligns Copilot Studio with modern model capabilities, consistent platform support, and long-term reliability. Claude Sonnet 4.5 will be moved to a retired state.

[When this will happen]

• April 30, 2026: Evaluation window opens. Makers can test and update agents to newer supported models. This evaluation window allows you to test and select the model that best meets your needs before automatic migration occurs.
• May 30, 2026: Claude Sonnet 4.5 moves to a retired state and phased automatic migration begins.
• June 30, 2026: Final migration deadline after deferral; all remaining agents are migrated automatically.

[How this affects your organization]

Who is affected

• Admins and makers using Microsoft Copilot Studio
• Organizations with Copilot Studio agents currently configured to use Claude Sonnet 4.5

What will happen

• Any agents still using Claude Sonnet 4.5 on May 30, 2026, will be automatically migrated to Claude Sonnet 4.6.
• From April 30 to May 30, 2026, makers can test and proactively migrate agents to Claude Sonnet 4.6 or another supported model to validate behavior before automatic migration begins.
• Automatic migration will occur in a phased rollout beginning May 30.
• Admins can enable a one-time 30-day deferral of automatic migration (until June 30) using the Continue using retired models toggle.
• After June 30, all remaining agents will be migrated automatically.
• Agent configurations, flows, integrations, security, compliance, and governance controls remain unchanged.
• Responses may vary after migration due to differences in model behavior (for example, tone, formatting, or response quality).
• Usage analytics and reporting will reflect the new model after migration.
• Agents not using Claude Sonnet 4.5 are not affected.

[What you can do to prepare]

We recommend that administrators and makers: 

• Review Copilot Studio agents in your tenant to identify any using Claude Sonnet 4.5.
• Test business-critical agents with Claude Sonnet 4.6 and/or Opus 4.6 during the April 30–May 30 evaluation window.
• If appropriate for your scenarios, you may also evaluate other supported models, such as Opus 4.6, during this period.
• If you encounter issues during evaluation, contact Microsoft Support through your standard support channels. 
• If you need more time to validate agents, you can defer automatic migration once for 30 days. To defer migration, enable the Continue using retired models toggle in Copilot Studio settings before May 30, 2026.
• Communicate expected response changes to stakeholders and helpdesk teams.
• Update internal documentation that references Claude Sonnet 4.5.
• Review Copilot Studio documentation for model selection and agent testing guidance.

Learn more:

• Continue using a retired AI model | Microsoft Copilot Studio | Microsoft Learn
• Microsoft Copilot Studio documentation | Microsoft Learn

[Compliance considerations]

Question	Answer
Does this change alter how existing customer data is processed, stored, or accessed?	Yes. Agents previously using Claude Sonnet 4.5 will process customer data using Claude Sonnet 4.6 after migration. The type of data processed does not change; only the underlying large language model is updated. Data residency, storage locations, and access controls remain unchanged.
Does this change introduce or significantly modify AI/ML or agent capabilities that interact with customer data?	Yes. This change replaces one large language model (Claude Sonnet 4.5) with a newer supported model (Claude Sonnet 4.6) for Copilot Studio agents. While agent configurations, flows, and integrations remain the same, responses may differ in tone, formatting, or quality due to model behavior differences.
Does this change alter how admins can monitor, report on, or demonstrate compliance activities?	Yes. After migration, usage analytics and reporting in Copilot Studio will reflect Claude Sonnet 4.6 as the active model. No reporting capabilities are removed, but historical and future analytics will reference the new model name.
Does this change include an admin control?	Yes. Admins and makers can proactively migrate agents during the evaluation window or enable a one-time 30-day deferral of automatic migration. These controls must be exercised before May 30, 2026.
Does this change allow end users to enable or disable the feature themselves?	Yes. Makers (with appropriate permissions) can select supported models for agents during the evaluation window. End users without maker permissions cannot control the migration.

Source: Microsoft

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