ChatGPT free users get unlimited text chats, default upgraded to GPT-5.6 Luna

On August 11, OpenAI announced the removal of message caps for ChatGPT free tier and Go tier users in pure text conversations. Starting August 10 local time, free and Go accounts can have unlimited text chats without message-count constraints.

The core change is that GPT-5.6 Luna replaces GPT-5.5 Instant as the default model for free and Go users. Luna is the smallest model in the GPT-5.6 family, designed for fast response and low cost, with improvements in language understanding, logical reasoning, and generation capability over its predecessor.

ChatGPT also added a new Think button for free users. When users encounter complex questions, they can click this button to let the model allocate more computation time for deep reasoning and produce more accurate answers. The feature is also unlimited in pure text scenarios, but combining it with file uploads, images, and other features still counts against separate quotas.

File uploads, image generation, and voice mode still retain their respective usage limits, with anti-abuse mechanisms in place. For Plus and Pro paid users, OpenAI also rolled out an optimized GPT-5.6 Sol model tailored for daily conversation. The new Sol delivers more focused answers, adjusts detail level to the question, avoids unnecessary formatting, and offers constructive corrections when simple agreement would not be useful. Paid users also received a new thinking-effort slider to tune the reasoning resources allocated to a query.