[OpenAI: GPT-5.1 Fully Rolled Out to All ChatGPT Users This Week] According to an OpenAI announcement, GPT-5.1 has been fully rolled out to all ChatGPT users this week. This version features significant improvements in adhering to custom instructions, reasoning accuracy, and conversational naturalness. GPT-5.1 supports adaptive reasoning, allowing it to intelligently extend thinking time for complex questions, resulting in clearer responses with fewer technical terms. GPT-5 users can continue using it for three months, while the Pro version will be updated to GPT-5.1 Pro.