OpenAI has announced a major update to ChatGPT that removes limits on text-based conversations for all users while introducing new AI models and reasoning features across its subscription tiers.
The update comes as ChatGPT surpasses one billion weekly users, marking a significant milestone for the AI platform.
Under the rollout, GPT-5.6 Luna will become the default model for Free and Go users, replacing GPT-5.5. OpenAI said the changes will give users unlimited text conversations, although separate usage limits will continue to apply to file uploads, image generation, voice interactions and other multimodal features.
The company is also introducing a new “Think” button for Free and Go users, allowing them to activate enhanced reasoning capabilities when tackling more complex questions.
For ChatGPT Plus and Pro subscribers, OpenAI is rolling out an upgraded version of GPT-5.6 Sol, designed to deliver faster, more concise responses for tasks such as writing, web research, planning, decision-making and general question answering.
The company noted that the updated GPT-5.6 Sol differs from the version currently powering Codex and ChatGPT Work, which remain unchanged.
Plus and Pro users will also gain access to a new thinking slider, enabling them to adjust how much reasoning the AI applies before generating a response based on the complexity of a task.
According to OpenAI, internal evaluations showed significant improvements in factual accuracy. Compared with GPT-5.5 Instant, factual errors were reduced by 62% in GPT-5.6 Luna and by 68% in GPT-5.6 Sol.
The upgraded GPT-5.6 Sol is available immediately for Plus and Pro subscribers, while the remaining updates for Free and Go users will roll out over the coming week. OpenAI said unlimited text chats and the new Think feature will become available to all eligible users next week.
