OpenAI has announced major changes for ChatGPT users, with Free and Go plan subscribers set to receive unlimited text chats without being automatically switched to a weaker model.

According to the company, GPT-5.6 Luna will become the default model for Free and Go users this week, replacing the existing GPT-5.5 Instant model.

OpenAI said users on these plans will also receive a new “Think” button next week. The feature will allow users to decide how deeply ChatGPT should analyze a question before generating a response.

The company clarified that while there will be no fixed usage limit for text conversations, restrictions will remain in place for other features, including file uploads and image generation.

The changes are expected to give Free and Go users more flexibility, particularly for longer conversations and tasks that require multiple follow-up questions.

Meanwhile, OpenAI has also announced an update for the GPT-5.6 Sol model available to Plus and Pro subscribers. The company said the upgraded model will provide more direct and concise responses while avoiding unnecessary details.

OpenAI also claims that the updated model will make fewer errors involving figures, dates, references, rules and assumptions.

According to the company’s internal evaluations, the updated GPT-5.6 Sol recorded about 68% fewer factual errors than GPT-5.5 Instant in financial, medical and legal questions.

The latest changes highlight OpenAI’s continued effort to improve ChatGPT’s reliability while giving users greater control over how the AI processes complex questions.

The new features will be rolled out in stages, with availability depending on the user’s plan and the specific ChatGPT feature being used.