ChatGPT's default model has been updated to GPT-5.5 Instant, a model that brings accuracy improvements with fewer hallucinations, especially in areas like medicine, law, and finance, according to OpenAI. GPT-5.5 Instant is more capable at tasks like analyzing images, answering STEM questions, and choosing when to use web search to provide a better answer.

ChatGPT's default model has been updated to GPT-5.5 Instant, a model that brings accuracy improvements with fewer hallucinations, especially in areas like medicine, law, and finance, according to OpenAI. GPT-5.5 Instant is more capable at tasks like analyzing images, answering STEM questions, and choosing when to use web search to provide a better answer.