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.” View image in new tab 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 […]

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