OpenAI Updates ChatGPT: GPT-5.6 Luna and New Reasoning Features

OpenAI has significantly updated ChatGPT:

Free and Go users can now use GPT-5.6 Luna in text chats without restrictions — a model whose capabilities are already sufficient for most everyday tasks. Additionally, a "Think" button is being introduced to the free tier, allowing the model to spend more time reasoning when answering complex questions.

Plus and Pro users have not been left without updates either. All new chats now run on GPT-5.6 Sol by default, and a slider has been added to adjust the amount of reasoning before the response. According to OpenAI, the new version of the model makes 68% fewer factual errors compared to GPT-5.5 Instant.

At the same time, the update only applies to standard ChatGPT chats. The GPT-5.6 Sol versions for Codex and Work remain unchanged.