Is GPT-4 already working for you?

I'm getting the following message even on the plus plan: "As of my knowledge cutoff date in September 2021, OpenAI has not released GPT-4. I am ChatGPT, an AI language model based on GPT-3. If OpenAI has released GPT-4 since then, I am not aware of it, and my responses will be limited to the knowledge and capabilities of GPT-3."