The long-awaited moment is here: ChatGPT is receiving an enormous upgrade to GPT-4.5. However, despite OpenAI calling GPT-4.5 its “largest and most knowledgeable model,” it comes with a few caveats that might see you continuing to use its older models for a while longer.
https://www.makeuseof.com/openai-launches-new-gpt-45-ai-model