WorldThe company said users would gain expanded access to text conversations, while messages involving file uploads or image generation would remain subject to separate usage limits. The company said users would gain expanded access to text conversations, while messages involving file uploads or image generation would remain subject to separate usage limits. In standard ChatGPT conversations, GPT-5.5 Instant remains the default model for everyday responses, while eligible paid plans can access GPT-5.6 Sol for more complex reasoning tasks. GPT-5.6 Luna is not selectable in standard ChatGPT conversations. The company said GPT-5.6 Sol is designed for complex work across areas including coding, research, science, cybersecurity, computer use and design.