Plus/Pro users of ChatGPT get an updated version of GPT-5.6 Sol now (more reliable facts, more focused answers, and a slider to control how much thought goes into the response), and GPT-5.6 Luna is now the default model for Free/Go users. Starting next week they get unlimited text chats & a new "Think" button for harder questions. No changes to Work/Codex with this release, just Chat.