Microsoft 365 is one of the most widely used software suites in the workplace — from local governments and public agencies to SMEs and large corporations. It is therefore worth noting that OpenAI's GPT-5.6 officially became the preferred model in Microsoft 365 Copilot on 9 July 2026, as confirmed by OpenAI on its official blog.

Three Models Behind the Upgrade

According to OpenAI, the GPT-5.6 family consists of three sub-models named Sol, Terra, and Luna. Microsoft has worked with OpenAI to optimise these specifically for office work within the 365 ecosystem. In addition, Microsoft's own Prometheus model and Microsoft Graph are used, giving Copilot access to contextual information from emails, documents, and chat messages — without customer data being used to train the foundation models, according to Microsoft.

"We're excited for customers to see what GPT-5.6 in Microsoft 365 can do, so they can work even more effectively with AI in the tools they use every day." — Nitin Agrawal, President, Copilot & Agents Core, Microsoft
GPT-5.6 Takes Over Microsoft 365 Copilot — 20 Million Users Upgraded - Bilde 1

What Changes in Practice?

The upgrade is set to deliver improvements across the entire 365 suite:

  • Word: Faster drafting with fewer instructions required from the user
  • Excel: Faster analysis from raw data to insight
  • PowerPoint: Improved automatic presentation generation
  • Copilot Chat: More precise natural-language handling and reasoning
  • Cowork: Enhanced support for real-time collaboration

Integration with Teams and Outlook for meeting summaries and email assistance remains unchanged.

20M
Paying Copilot users
90%
Share of Fortune 500 companies using Copilot

The Numbers Behind the Productivity Claims

Microsoft and independent parties have conducted several studies on the Copilot effect. There is good reason to read these with a critical eye — many were commissioned by or carried out in collaboration with Microsoft itself.

That said, the figures cited are relatively consistent: Microsoft's own early-adopter studies find an average time saving of 14 minutes per user per day. A UK government pilot test reportedly yielded 26 minutes of daily savings and an adoption peak of 83 percent, according to the research team. A Forrester analyst report, commissioned by Microsoft for a hypothetical organisation of 25,000 employees, estimates a 116 percent return on investment and a net present value of just over $19.7 million over three years.

Data from task-based experiments show that users were on average 29 percent faster, and nearly four times faster at producing meeting summaries.

One independent source — Forrester — is involved in the underlying data, but the study was commissioned by Microsoft. The results should be interpreted accordingly.

Pricing and Availability

Copilot is sold as an add-on to existing Microsoft 365 licences. For enterprises with more than 300 users, the price is $30 per user per month. Smaller businesses receive a discounted rate of $21 per month until 30 September 2026 — after which it is unclear whether this rate will continue.

Competition with Google Workspace

Microsoft's update comes as Google Workspace with Gemini models offers comparable features within its own ecosystem — including automated meeting notes in Meet, AI-powered analysis in Sheets, and video generation via Google Vids. For organisations already deeply embedded in the Microsoft platform, however, switching to competing solutions carries a high cost, and the GPT-5.6 upgrade gives Copilot a potential boost without requiring users to change tools.

Whether GPT-5.6 actually delivers meaningfully better results than the previous generation in day-to-day use remains to be seen — but for the more than 20 million paying users, the transition happens automatically and at no additional cost.