OpenAI is giving ChatGPT free and Go tier users unlimited text chats starting next week, and upgrading their default model to GPT-5.6 Luna. For Plus and Pro users, GPT-5.6 Sol is updated to be more reliable with facts and offers a new slider for reasoning depth.
From the source
OpenAI is making a big change for ChatGPT users on its free and Go tiers: Starting next week, users on those tiers will be able to have unlimited text chats with the chatbot, according to OpenAI.
theverge.com