OpenAI’s GPT-6.1 Sol shows dramatic improvements in legacy code migration including COBOL

On September 22, 2026, OpenAI announced GPT-6.1 Sol, an upgraded version of its mid-tier AI model. It’s available through the OpenAI API and is rolling out inside ChatGPT Work and Codex for eligible Plus, Pro, Business, Enterprise, and Edu users. On October 22, The New Stack reported that OpenAI’s internal COBOL migration test reached 86.6% accuracy at low reasoning effort and 97.9% at higher effort. That means turning decades-old business code into modern programming languages. (For the launch basics, see our GPT-6.1 Sol availability and pricing explainer .) So should you care? If you run a bank, an insurer, or a government IT shop, this is worth watching. If you’re an everyday ChatGPT user, probably not yet, because OpenAI says the model isn’t yet available in regular ChatGPT chats.