OpenAI has quietly removed one of its most visible product barriers: the daily cap on text-based conversations in ChatGPT. The move, announced alongside a new flagship model, applies to every tier of the service and lands as the platform surpasses one billion weekly users. Main Developments Free and Go tier users will no longer face limits on text chats, a change that arrives with the GPT-5.6 Luna model as the default engine, replacing GPT-5.5. Both groups also receive a new Think button, which manually boosts reasoning power for complex queries. Separate restrictions remain in place for files, images, voice, and image generation, so the unlimited label applies strictly to text interactions. OpenAI framed the update as a broadening of access rather than a removal of all usage guardrails. Read also: Snowflake hacker pleads guilty to 165-company data theft Plus and Pro subscribers see their own upgrade path with GPT-5.6 Sol, a variant tuned for quick tasks like web research, planning, writing, and decision-making. The company says this model produces more compact and robust answers, and it is distinct from the Sol version used in Codex and Work, which remains unchanged. Paid users also gain a thinking slider that adjusts how much deliberation the model applies to a response, letting them balance speed against depth. Internal evaluations show factual errors fell 62% with Luna and 68% with Sol compared to GPT-5.5-Instant. Background ChatGPT has grown rapidly since its debut, reaching the billion-weekly-user milestone that OpenAI cited in its announcement. The company has historically tiered access to its models, reserving advanced capabilities for paying subscribers while offering limited free usage to drive adoption. This rollout continues that pattern but shifts the boundary. Free users get parity on text volume, while paid tiers differentiate through model quality, reasoning controls, and priority access to newer features like the thinking slider. Why It Matters Eliminating text caps removes a major friction point for casual users who may have hit limits during heavy research or writing sessions. For OpenAI, the change signals confidence in its infrastructure and a strategic bet that broader free access will convert more users to paid plans over time. The reasoning-focused Think button and slider also highlight a competitive push toward transparency in AI decision-making. By letting users control how much "thought" goes into an answer, OpenAI is addressing a common critique that model outputs lack explainability. What's Next The updated GPT-5.6 Sol model is available to Plus and Pro users today. Free and Go users will see the Luna rollout and unlimited text chats arrive this week, with the Think button following next week. OpenAI has not disclosed whether further limits will be introduced for other modalities or how the thinking slider will evolve based on user feedback.