OpenAI rolled out its biggest ChatGPT shake-up in months on Thursday 6 August, and for once the free crowd got the good stuff too.
Luna becomes the default brain
Every ChatGPT user is being moved onto a new default model, GPT-5.6 Luna, replacing the old default, GPT-5.5 Instant. Luna arrived in early July and was built for speed. OpenAI says its own testing found responses containing at least one factual error were 62% less common with Luna than with the old default, and it reported a 68% drop for the upgraded GPT-5.6 Sol. Those are OpenAI’s internal numbers, so keep your usual pinch of salt handy, but the direction of travel is welcome.
Unlimited chats and a Think button
Free users, and people on the cheap Go plan, get unlimited text chats. They also get a new ‘Think’ button that lets you tell ChatGPT to put more reasoning into a hard question instead of blurting the first thing that comes to mind.
Plus and Pro subscribers get an improved GPT-5.6 Sol tuned for everyday jobs like quick questions, web research, planning, writing and decisions. OpenAI says this version gives more focused answers, with less needless formatting, a steadier tone and fewer mistakes. They also get a ‘slider’ for dialling how much thought ChatGPT spends on a reply.
The catch: it lands in stages
Do not panic if your app looks identical tonight. The Sol update went live for Plus and Pro straight away, the broader changes reach Free and Go users across this week, and the unlimited chats and Think button follow next week. Rollouts like this always dribble out by region and platform, so patience.
Why now
Context matters. Cheap Chinese open-weight models have piled pressure on OpenAI and Anthropic to prove their pricier models earn their keep. OpenAI cut prices on two GPT-5.6 models, Luna and Terra, in late July, and those cuts used to arrive months after a launch, not weeks. Handing unlimited chats to free users, on a platform that just passed a billion weekly users, is the move of a company keen to keep rivals out in the cold.
Is it worth changing anything
If you live in ChatGPT, two habits are worth forming. Reach for the Think button, or the slider, when accuracy matters more than speed, so maths, code, or anything you will paste into a client email. And leave it off for the quick reword-this-paragraph jobs, since higher reasoning chews through your limits faster. Free users finally getting unlimited text is the headline, but the reasoning controls are the part that will actually change your results. The naming remains a mess, mind you: Luna, Terra, Sol, a slider and a button is a lot to keep straight for a product meant to be simple.
Did you know: ChatGPT now claims more than a billion weekly users, which is roughly one in eight people on the planet outsourcing their emails to a chatbot.
Sources
- Axios: OpenAI makes major upgrades for free and paid ChatGPT users
- AI Insider: OpenAI expands ChatGPT access with new models
- OpenAI: GPT-5.6
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