OpenAI has updated ChatGPT to offer a more concise version of its GPT-5.6 Sol model to paying subscribers, while restricting free accounts to the weaker GPT-5.6 Luna.
The company states the new Sol variant reduces unnecessary detail and formatting. It provides direct answers for simple queries and fuller responses for complex tasks, keeping key recommendations easy to find.
OpenAI claims improved factual accuracy in an internal test using finance, medicine, and law prompts. Responses with at least one error dropped by about 62 per cent for GPT-5.6 Luna and 68 per cent for GPT-5.6 Sol compared to GPT-5.5 Instant. These figures have not been independently verified.
The update applies only to ChatGPT. GPT-5.6 Sol remains unchanged in ChatGPT Work and Codex.
Paying users get more control over reasoning
A new slider allows paying users to adjust how much effort ChatGPT puts into a response. Lower settings suit everyday questions, while higher settings are meant for planning, research, and coding. The slider was already available in ChatGPT Work.
OpenAI says it wants quick answers and deeper reasoning to feel like one model rather than two with different tones. A developer recently explained which of the five settings fits which type of task. The slider works on web, mobile, and desktop.
It is worth asking whether these controls actually help people use AI better. Users largely ignored the model switcher, and picking the right model for a task likely mattered more than choosing among five reasoning levels. Adding more knobs to turn does not make the experience better.
Free users get more chats but a weaker model
GPT-5.6 Luna will become the default for Free and Go users later this week, according to OpenAI’s release notes. Unlimited text chats and a new “Think” button for harder questions will follow next week, though limits on file uploads, image generation, and other tools will stay in place.
Luna may perform well for its size, but smaller models are generally more error-prone and less reliable. A case involving the previous Instant model, which produced a completely wrong data analysis compared to its larger reasoning counterpart, made that risk clear. Since the Think button only lets the smaller Luna reason longer rather than switching to a stronger model, free users lose access to OpenAI’s most powerful reasoning altogether.
