MC1194070 – (Updated) Microsoft 365 Copilot: Declarative agents model upgrade to GPT-5.1

Product:

Copilot, Microsoft 365 Copilot

Platform:

Online, World tenant

Status:

Change type:

Updated message, New feature, User impact, Admin impact

Links:

Details:

Summary:
Microsoft 365 Copilot declarative agents will upgrade to the GPT-5.1 model with an auto architecture, rolling out worldwide from mid- to end-January 2026. The upgrade requires no admin changes, is enabled by default, and offers advanced reasoning for complex queries. No compliance issues identified.

Details:
Updated January 15, 2026: We have updated the timeline. Thank you for your patience.
[Introduction]
Microsoft 365 Copilot declarative agents are upgrading to the GPT-5.1 model, which uses an "auto" architecture. The orchestrator will automatically select the best model for each scenario, either the fast "chat" model or the advanced reasoning model, based on the user prompt.
[When this will happen]
General Availability (Worldwide): Rollout will begin mid-January 2026 (previously early January) and is expected to complete by end of January 2026 (previously mid-January).

Change Category:
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Scope:
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Release Phase:

Created:
2025-12-11

updated:
2026-01-16

Task Type

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Docu to Check

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MS How does it affect me

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MS Preperations

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MS Urgency

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MS workload name

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summary for non-techies**

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Direct effects for Operations**

Performance Variability
The upgrade to GPT-5.1 may lead to unpredictable performance changes, affecting response times and accuracy of outputs, especially during the initial rollout phase.
   - roles: End Users, IT Support
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2026/01/15/whats-new-in-microsoft-365-copilot-2026/

User Adaptation
Users may struggle to adapt to the new advanced reasoning capabilities, leading to confusion and decreased productivity as they learn to utilize the new features effectively.
   - roles: End Users, Training Coordinators
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2026/01/15/whats-new-in-microsoft-365-copilot-2026/

Integration Issues
The automatic selection of models may cause integration issues with existing workflows, leading to disruptions in user experience and potential data handling errors.
   - roles: End Users, Business Analysts
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2026/01/15/whats-new-in-microsoft-365-copilot-2026/

Configutation Options**

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Opportunities**

Enhanced User Experience through Advanced Reasoning
The upgrade to GPT-5.1 introduces an advanced reasoning model that can handle complex queries more effectively. This can significantly improve user experience by providing more accurate and context-aware responses, thereby reducing the time users spend searching for information or clarifications.
   - next-steps: Conduct training sessions for users to familiarize them with the capabilities of the new advanced reasoning model. Gather feedback to assess improvements in user satisfaction and efficiency.
   - roles: End Users, Product Managers, Customer Support Teams
   - references: https://www.microsoft.com/en-us/microsoft-365/blog/2026/01/15/whats-new-in-microsoft-365-copilot-2026/

Operational Efficiency in IT Support
With the upgrade, IT support teams can leverage the advanced reasoning capabilities to automate responses to common user queries and issues. This can reduce the workload on support staff and improve response times.
   - next-steps: Identify common support queries that can be automated with the new capabilities and develop a knowledge base that integrates with the Copilot system.
   - roles: IT Support Teams, System Administrators, Helpdesk Managers
   - references: https://www.techrepublic.com/article/how-ai-is-transforming-it-support/

Data-Driven Decision Making
The new auto architecture allows for more nuanced data analysis and reporting capabilities, enabling teams to make better-informed decisions based on the insights generated from complex queries.
   - next-steps: Integrate the Copilot's advanced reasoning features into existing data analytics workflows to enhance reporting accuracy and insights generation.
   - roles: Data Analysts, Business Intelligence Teams, Executives
   - references: https://www.forbes.com/sites/bernardmarr/2023/05/10/how-ai-is-changing-the-way-businesses-make-decisions/

Potentional Risks**

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Data Protection**

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IT Security**

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Hypothetical Work Council Statement**

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DPIA Draft**

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explanation for non-techies**

Microsoft is updating its 365 Copilot with a new technology called GPT-5.1. Think of this update like upgrading from a regular car to a hybrid car. Just like a hybrid car can switch between using gas and electricity to give you the best performance and efficiency, the new GPT-5.1 model can automatically choose the best way to handle your requests. It can decide whether to use a faster, simpler method or a more complex, advanced method depending on what you need.

This change is happening worldwide between mid and end of January 2026. If you use Microsoft 365 Copilot, you don't need to do anything special. It's like getting a software update on your phone that happens automatically in the background. You won't need to change any settings or configurations; everything will be set up for you by default.

There are no compliance issues with this update, so you don't have to worry about any new rules or regulations. It's like getting a new feature in your car that doesn't require any additional paperwork or permissions.

In summary, this upgrade is designed to make Microsoft 365 Copilot smarter and more efficient without requiring any extra effort from you. It's a seamless transition to a more advanced system that will handle complex tasks more effectively.