chatgpt-4o-latest is the current model used in ChatGPT (optimized for chat). Updated this week. https://platform.openai.com/docs/models/chatgpt-4o-latest
gpt-4o, which supports function calling, was updated last year (it points to gpt-4o-2024-08-06 . Team’s working on a new gpt-4o-2025-XX... model, which will carry over some of the improvements you see in ChatGPT. Should arrive in the coming weeks!