OpenAI today said it is making GPT–5.6 Luna the default model for Free and Go ChatGPT users, giving them access to a newer, more capable model to replace GPT–5.5 Instant. The company is letting Free and Go users access unlimited text chats, with no text-based rate limits. Limits will still apply for file uploads, images, and other ChatGPT tools. There's also a new Think button coming that turns on higher reasoning.
For Plus and Pro users, GPT–5.6 Sol is more reliable with facts and gives more focused answers. OpenAI added a slider to let users select how much thought ChatGPT puts into a response, plus the company tweaked the detail the model offers for each question to prevent it from giving extra information when it's not needed.
OpenAI says GPT–5.6 Sol will avoid unnecessary formatting and will offer a "helpful correction when simply agreeing wouldn't be useful." It is also supposed to make fewer mistakes, especially when answers depend on dates, numbers, sources, rules, or assumptions. The Sol update is only for Chat, and the version for Work and Codex is unchanged.
ChatGPT's Instant and Thinking experiences have a more consistent tone and behavior so it doesn't feel like switching to a model with a different tone or style.
Plus and Pro users have access to the updated GPT–5.6 Sol and the slider in ChatGPT starting today. GPT–5.6 Luna is becoming the default model for Free and Go users this week, with unlimited text chats and the Think button coming next week.
The changes apply to the ChatGPT app for iPhone, iPad, and Mac.
