OpenAI will remove text-based chat restrictions for all users on ChatGPT, which recently surpassed 1 billion weekly users, the company announced today.
The new GPT-5.6 Luna model enhances this experience and replaces GPT-5.5 as the default model for Free and Go users.
Both users will have a new “Think” button that allows them to choose higher reasoning power for complex questions. OpenAI said there will still be separate limits for files, images, audio, and image generation.
This update also brings changes to Plus and Pro users. They will have access to an upgraded GPT-5.6 Sol model suitable for quick tasks such as asking questions, web research, advising, planning, writing, and decision-making. The company noted that this new model offers a more compact and robust answer. (Notably, this is a separate version of GPT-5.6 Sol used for Codex and Work, and remains unchanged.)
ChatGPT Plus and Pro users also have a thought slider to adjust how much thought the model puts into its answers. You can adjust the thinking slider based on the complexity and steps required to solve your query.
According to OpenAI, an internal evaluation found that GPT-5.6 Luna had 62% fewer factual errors and GPT-5.6 Sol had 68% fewer factual errors compared to GPT-5.5-Instant.
An updated version of GPT-5.6 Sol is rolling out to Plus and Pro users today, and other changes for Free and Go users are expected to arrive this week. Next week, users will have access to unlimited text chat and a new “think” button for tough questions.
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