More Models, One Copilot: Claude Opus 5.5 and GPT-6 Sol in Microsoft Copilot
On September 22, 2026, Microsoft began rolling out two new frontier models in Copilot: Anthropic's Claude Opus 5.5 and OpenAI's GPT-6 Sol. They are arriving in Word, Excel, PowerPoint, Copilot Chat, Cowork, and Copilot Studio. Microsoft's reasoning: no single model is ideal for every task. But response quality depends not only on the model — it also depends on what Copilot knows about a specific company's work.