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GPT-5 becomes the default Copilot model
GPT-5 will become the default Microsoft 365 Copilot model in a phased rollout from October to November 2025. Initially, users can toggle GPT-5 on or off; later, it becomes mandatory with no opt-out. GPT-5 offers faster, more accurate responses with dynamic model routing and reasoning features.
Introduction
We’re updating the default experience for users with the Microsoft 365 Copilot license by introducing GPT-5 as the standard model. GPT-5 is OpenAI’s most advanced language model, designed to deliver faster, more accurate, and more context-aware responses. It features dynamic model routing, which automatically selects the best-performing variant for each prompt—using high-throughput models for quick replies and deeper reasoning models for complex tasks. This change simplifies the user experience and enhances performance across all Copilot endpoints.
When this will happen:
- General Availability (Worldwide): Phased rollout begins late October 2025 and completes by late November 2025.
How this affects your organization:
- Who is affected: All users with a Microsoft 365 Copilot license across web, desktop, and mobile experiences.
- What will happen:
- The rollout will occur in two phases:
- Phase 1 (web, desktop): GPT-5 toggle is enabled by default. Users can choose to disable GPT-5 via the toggle and revert to previous models.
- Phase 2 (web, desktop, mobile): GPT-5 becomes the default model. Users will no longer be able to opt out, and the GPT-5 toggle button will be removed.
- The GPT-5 default experience will also apply to Copilot Chat in the Microsoft 365 apps. The exception is on Teams mobile, which is planned to rollout beginning late November 2025.
- Copilot will automatically trigger GPT-5 reasoning based on prompt complexity.
- Users will be able to bypass GPT-5 reasoning and get a direct response by selecting “Get a quick answer.”
- Users will be able to bypass GPT-5 reasoning and get a direct response by selecting “Get a quick answer.”
What you can do to prepare:
- No admin action is required to enable this feature.
- Communicate the phased rollout to helpdesk and support teams.
- Update internal documentation to reflect the default use of GPT-5 and how to bypass reasoning if desired.
- Review any training materials or user guides that reference the GPT-5 toggle.
Compliance considerations
| Compliance Area | Explanation |
|---|---|
| Introduces or modifies AI/ML capabilities | GPT-5 introduces enhanced model routing and deeper reasoning capabilities that interact with user data. |
| Provides new ways of interacting with generative AI | Users will now interact with GPT-5 by default, without manual model selection. |
| Includes admin control | Admins can monitor usage via existing Copilot reporting tools but cannot disable GPT-5 as default after Phase 2. |
| Allows a user to enable and disable the feature themselves | Users can use the toggle to opt out of GPT-5 during Phase 1; Users cannot opt out during Phase 2, but they can bypass GPT-5 reasoning to get a direct response. |
Message ID: MC1176368
