OpenAI rolls out GPT-5.6 Luna as default ChatGPT model, removes text chat limits for free tier users

OpenAI has announced significant enhancements to ChatGPT, aiming to provide users with expanded access and cutting-edge AI models. One of the most notable changes is the introduction of the GPT-5.6 Luna model for free-tier users, who will now enjoy unlimited text chats, replacing the previous GPT-5.5 model. In addition to this, Pro and Plus subscribers will receive the upgraded GPT-5.6 Sol, which promises enhanced performance and more accurate responses. A key feature of these upgrades includes a new slider control for paid users, allowing them to customize the depth of reasoning applied to their queries. Free users will also benefit from a "Think" button, designed to facilitate higher-level reasoning for more complex questions. The GPT-5.6 Luna model is part of the advanced GPT-5.6 family, which aims to deliver superior efficiency and performance. According to OpenAI, this model is less prone to factual inaccuracies compared to its predecessor, GPT-5.5 Instant. It stands out as the fastest and most cost-effective option within its family, handling up to 1,050,000 tokens in context and generating responses of up to 128,000 tokens. Notably, it also supports multimodal inputs, allowing users to process both text and images seamlessly. One of the most exciting aspects of this upgrade is the provision of unlimited text chats for free users, eliminating standard rate limits for everyday conversations. However, it's important to note that certain limitations will still apply to features like file uploads and image processing. The new "Think" button will empower free users to tackle complex inquiries with enhanced reasoning capabilities. For Plus and Pro users, the GPT-5.6 Sol model introduces improved reasoning controls and more precise, focused answers. OpenAI emphasizes that this model adapts its detail level to the nature of the question, avoiding unnecessary formatting and providing useful corrections when simple agreement isn't sufficient. Users will be able to select their preferred reasoning depth through the new slider on web, mobile, and desktop platforms, choosing from Instant, Medium, High, and Extra High settings based on the complexity of their prompts. This allows ChatGPT to automatically adjust its level of reasoning as needed, ensuring a tailored conversational experience.