ChatGPT’s free tier gets GPT 5.4 mini model with improved coding capabilities OpenAI just announced its latest models, GPT 5.4 mini and nano, with the former now available to free ChatGPT users. https://9to5google.com/2026/03/17/openai-gpt-5-4-mini-nan… https://9to5google.com/2026/03/17/openai-gpt-5-4-mini-nan…