OpenAI has announced a series of changes to ChatGPT that will bring new features to both free and paid users, including unlimited text chats for free and Go subscribers.

The company is also shifting default model to GPT-5.6 Luna this week, while Plus and Pro users will get an upgraded GPT-5.6 Sol, Axios reports.

According to the American news outlet, free AI plans from frontier labs now offer more intelligence than most people will use, while enterprises are still working out how to budget for advanced capabilities.

OpenAI said responses containing at least one factual error were 62 percent less common with Luna than with the previous default model, GPT-5.5 Instant. Luna, which debuted in early July, was built for speed.

Free and Go users will have unlimited text chats. They will also get a new "Think" button that allows users to select higher reasoning for harder questions, it added.

Plus and Pro users will get GPT-5.6 Sol, which OpenAI says has been improved for “everyday conversations and tasks, like quick questions, web research, advice, planning, writing, and decisions”.

The company says the updated model delivers more focused answers, with less unnecessary formatting, a consistent tone and fewer mistakes.

It will also feature a new slider tool for choosing how much thought ChatGPT puts into an answer.

Axios reported that cheaper Chinese open-weight models have increased pressure on OpenAI and Anthropic to prove their models justify their higher costs.

OpenAI reportedly cut the prices of two of its GPT-5.6 models, GPT-5.6 Luna and GPT-5.6 Terra, last week.

Such price cuts have previously come months after a model launches rather than weeks.