OpenAI removed text-chat limits for all ChatGPT users and introduced GPT-5.6 Luna as the default model for free users, with a new reasoning tool to tackle complex questions.
Plus and Pro subscribers gain access to GPT-5.6 Sol, which delivers 68% fewer factual errors than the previous generation.
The feature rollout begins this week, arriving as ChatGPT surpasses 1 billion weekly users.
What happened
OpenAI removed limits on text-based chats for all ChatGPT users and is deploying GPT-5.6 Luna as the default model for Free and Go users, replacing GPT-5.5. A new "Think" button lets Free and Go users select higher reasoning for complex questions. Plus and Pro users gain access to GPT-5.6 Sol, with a thinking slider to adjust reasoning depth. The rollout begins this week, with unlimited text chats and the Think button arriving next week.
Why it matters
The change levels up free-tier access to competitive reasoning capabilities—a notable shift in how OpenAI distributes advanced features. Internal evaluation found factual errors 62% less common for GPT-5.6 Luna and 68% less common for GPT-5.6 Sol than the prior GPT-5.5-Instant. This arrives as ChatGPT recently crossed 1 billion weekly users, suggesting OpenAI is investing in retention and engagement across all user tiers.
What to watch
The new GPT-5.6 Sol for Plus and Pro users is available today, while Free and Go features roll out this week and next. Separate limits remain for files, images, voice, and image generation. The GPT-5.6 Sol for Codex and Work remains unchanged.
OpenAI announced today that it is removing limits on text-based chats for all ChatGPT users, a move tied to the platform's recent milestone of crossing 1 billion weekly users. The company is introducing two new models to power this expanded access: GPT-5.6 Luna, which will be the default for Free and Go users and replaces GPT-5.5, and GPT-5.6 Sol, an upgraded version available to Plus and Pro users.
Free and Go users will also receive a new "Think" button that enables them to select higher reasoning power when tackling complex questions. Plus and Pro users are gaining access to a thinking slider that lets them adjust how much reasoning the model applies to each answer, calibrated based on the complexity and number of steps involved in solving a query. According to OpenAI, GPT-5.6 Sol is optimized for quick tasks including questions, web research, advice, planning, writing, and making decisions, delivering more compact and robust answers than its predecessor. The company emphasized that this Sol version is distinct from the GPT-5.6 Sol used for Codex and Work products, which remain unchanged.
The performance improvements are backed by internal evaluation: compared to GPT-5.5-Instant, factual errors were 62% less common for GPT-5.6 Luna and 68% less common for GPT-5.6 Sol. OpenAI clarified that limits will continue to apply separately to files, images, voice, and image generation. The updated GPT-5.6 Sol is available to Plus and Pro users as of today, while the other changes—including unlimited text chats and the Think button for Free and Go users—will begin rolling out this week, with full availability arriving next week.
OpenAI's announcement comes as ChatGPT has reached a significant milestone of 1 billion weekly users, signaling the platform's dominance in consumer AI adoption. The removal of text-chat limits for free users marks a deliberate shift in OpenAI's freemium strategy—prioritizing engagement and user retention over restricting features to paid tiers. By introducing GPT-5.6 Luna and Sol, OpenAI is distributing reasoning improvements across the entire user base, suggesting internal evaluations have validated the models' quality gains.
The introduction of a "Think" button and thinking slider across all tiers reflects a design philosophy that puts control over reasoning depth into users' hands rather than enforcing a one-size-fits-all response. Free users can now opt into higher reasoning when needed, while paying users can fine-tune the balance between speed and depth. The fact that file, image, voice, and image generation remain separately limited indicates OpenAI is ring-fencing resource-intensive features, likely for cost and infrastructure reasons, while betting that unlimited text chat will sustain growth and engagement.
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