OpenAI has announced that it’s lifting restrictions on text-based conversations across ChatGPT for all users, a move that coincides with the platform recently surpassing 1 billion weekly active users. This experience will be powered by the newly introduced GPT-5.6 Luna model, which becomes the default for both Free and Go users, taking over from GPT-5.5. Alongside this, these users will see a fresh “Think” button, allowing them to opt into higher reasoning capabilities when tackling more complex queries. The company clarified that separate usage caps will remain in place for files, images, voice, and image generation.

The rollout also brings notable upgrades for Plus and Pro subscribers. They’ll now have access to an enhanced GPT-5.6 Sol model, designed to excel at quick-response tasks like answering questions, conducting web research, offering advice, planning, writing, and decision-making. According to the company, this iteration delivers more concise and reliable answers. Interestingly, this version is distinct from the GPT-5.6 Sol used in Codex and Work environments, which remains unchanged. For ChatGPT Plus and Pro users, a new thinking slider is being introduced, giving them control over the depth of reasoning the model applies to each response. This slider can be adjusted based on the complexity of the query and the number of steps required to solve it.

In internal evaluations, OpenAI reports that factual inaccuracies dropped by 62% with GPT-5.6 Luna and 68% with GPT-5.6 Sol, compared to the previous GPT-5.5-Instant. The upgraded GPT-5.6 Sol is available to Plus and Pro users starting today, while the changes for Free and Go users will begin rolling out this week. By next week, all users will gain access to unlimited text chats and the new Think button for tackling harder questions.