OpenAI’s GPT-5.6 powers Microsoft 365 Copilot across workplace apps

OpenAI said GPT-5.6 became the preferred model in Microsoft 365 Copilot across Word, Excel, PowerPoint, Chat and Cowork, putting its newest flagship system at the center of Microsoft’s workplace software stack. The update reinforces a partnership that still anchors one of Microsoft’s most important enterprise products, even as speculation continues over how long the two companies will remain so tightly linked.

OpenAI described GPT-5.6 as its latest flagship model series and said it is built for stronger performance per dollar and for on-demand use in complex tasks. The placement inside Microsoft 365 Copilot matters because the product is not a standalone chatbot. Microsoft has long positioned Copilot as an assistant woven into Microsoft 365 apps, Microsoft Graph and enterprise workflows, which means model changes can ripple through document drafting, spreadsheet analysis, presentations and workplace chat.

Microsoft’s own materials still frame OpenAI models as central to Copilot. The company says Microsoft 365 Copilot uses the latest OpenAI models and gives customers model-choice and priority options. It also says OpenAI-operated models can be enabled or disabled by administrators in the Microsoft 365 admin center, giving organizations control over whether those systems are active in their environment. That setup leaves Microsoft dependent on OpenAI for a core layer of the product while still trying to present the service as manageable for enterprise buyers.

The commercial backdrop is just as important. Microsoft 365 Copilot Business was discounted from July 1, 2026, through September 30, 2026, with pricing shown at starting from $18 per user per month on annual pay-monthly terms during the promotion. For customers weighing long-term commitments, the pricing push sits beside a product architecture that is still closely tied to OpenAI’s model roadmap, not to a fully independent Microsoft system.

Microsoft has previously said that bringing GPT-5 to Copilot on the day of its release was part of its commitment to make OpenAI’s newest models available within 30 days. That pledge underscores the technical cadence between the companies: Microsoft is not just licensing a model family, it is building release timing around it. GPT-5.6 now extends that pattern into the apps many companies use every day, making Copilot less a detached Microsoft platform than a bet on a partnership that remains both commercially valuable and strategically fragile.