SAN FRANCISCO, CALIFORNIA / RankWire.AI / – OpenAI is expanding ChatGPT access for Free and Go users with GPT-5.6 Luna as the default model. The company said unlimited text chats will become available next week, subject to safeguards against abuse. Free users will also gain a Think button for questions that need deeper reasoning. Limits will remain for file uploads, image generation and other tools. OpenAI announced the changes on August 6 as part of a broader update to ChatGPT.
GPT-5.6 Luna will become the default model for Free and Go accounts during the current rollout week. Unlimited text conversations and the Think button will follow next week. The Think control gives Luna more time to work through harder questions before providing an answer. OpenAI said the unlimited text access remains subject to abuse guardrails. The change applies to text conversations rather than every ChatGPT feature, so separate usage restrictions will continue for tools that require additional processing.
The expansion comes as ChatGPT serves a large global user base across everyday and professional tasks. OpenAI said one billion people use ChatGPT each week for searches, planning, research, writing and other activities. The company introduced the GPT-5.6 model family in July, including Sol, Terra and Luna. Luna is positioned as the fastest and most cost-efficient model in that family. The latest update places Luna at the center of the standard experience for users on Free and Go plans.
Paid ChatGPT plans receive updated GPT-5.6 Sol
ChatGPT Plus and Pro users are receiving an updated version of GPT-5.6 Sol for everyday conversations. Sol now powers both instant responses and deeper reasoning for those subscribers. OpenAI said the update produces more focused answers and reduces unnecessary detail when simpler responses are enough. Plus and Pro users also receive a reasoning slider across web, mobile and desktop. The control lets users choose how much processing ChatGPT applies to a question, including tasks involving research, planning, writing and coding.
OpenAI also reported improvements in factual accuracy based on its internal testing. The evaluation covered financial, medical and legal prompts that required factual detail. Responses containing at least one factual error were about 62% less common with GPT-5.6 Luna than with GPT-5.5 Instant. For GPT-5.6 Sol, OpenAI reported a reduction of about 68%. The company said the updated Sol model also handles dates, numbers, sources, rules and assumptions more reliably when those details affect an answer.
New access comes with safety and tool limits
The company said its latest models include additional protections for users it believes are under 18. OpenAI trained the systems to avoid romantic roleplay, age-restricted challenges and claims that could replace real-world relationships. The models also include age-related boundaries for sexual content, eating disorders, dangerous activities, restricted goods and graphic violence. OpenAI said it added new evaluations for responses involving younger users. The unlimited text feature will still operate within the company’s abuse safeguards when it becomes available to Free and Go accounts.
The ChatGPT update applies specifically to the main chat experience. OpenAI said the GPT-5.6 Sol versions used in ChatGPT Work and Codex are not changing with this release. Paid subscribers can access the updated Sol model and reasoning slider now. Free and Go users are receiving Luna as their default model this week, followed by unlimited text chats and the Think button next week. File uploads, images and other tools will continue to carry separate limits even after unlimited text messaging becomes available.