OpenAI removes text chat limits for ChatGPT free users

OpenAI has removed message limits for free ChatGPT users while introducing new model tiers and reasoning features. Free and Go users will now use the GPT-5.6 Luna model by default, while Plus and Pro users will have access to an upgraded GPT-5.6 Sol model. Both tiers gain a new "Think" button allowing users to request higher reasoning power for complex questions. Plus and Pro users also receive a thinking slider to adjust the depth of model reasoning. Limits for files, images, voice, and image generation remain in place. Internal testing shows GPT-5.6 Luna produces 62% fewer factual errors compared to GPT-5.5-Instant, while GPT-5.6 Sol reduces errors by 68%. The announcement comes as ChatGPT crosses one billion weekly active users. Updates roll out this week for Plus and Pro users, with free user changes arriving next week.