https://arstechnica.com/information-technology/2023/07/openais-most-powerful-chatbot-api-rolls-out-for-all-paying-customers/

On Thursday, OpenAI announced that all paying API customers now have access to the GPT-4 API. It also introduced updates to chat-based models, announced a shift from Completions API to the Chat Completions API, and outlined plans for deprecation of older models.