The changes affect both free and paid users, with GPT-5.6 Luna becoming the default model for Free and Go subscribers and GPT-5.6 Sol receiving a number of improvements for Plus and Pro users. The version of GPT-5.6 Sol used for Work and Codex is not changing as part of this release, it added. We’re making better intelligence easier to access in ChatGPT for everyone: – GPT-5.6 Sol now powers both Instant and deep reasoning for Plus & Pro users, delivering more factual, focused responses. pic.twitter.com/JXhmj5GLTH — OpenAI (@OpenAI) August 6, 2026Unlimited Text Chats, New “Think” Feature Coming SoonOpenAI also announced that unlimited GPT-5.6 Luna chat access for both Free and Go users will be available soon. GPT-5.6 Sol New FeaturesMeanwhile, OpenAI is updating GPT-5.6 Sol for ChatGPT Plus and Pro subscribers.