https://techcrunch.com/2023/03/14/microsofts-new-bing-was-using-gpt-4-all-along/

When Microsoft announced the new AI-enabled Bing, which it built on top of OpenAI’s GPT models, neither company would confirm which version of GPT was being used beyond saying it was a next-gen version of the model that powered ChatGPT. Today, OpenAI announced GPT-4, a significant update to GPT-3.5. As it turns out, Bing was using it all along.

“We are happy to confirm that the new Bing is running on GPT-4, which we’ve customized for search,” Microsoft’s Yusuf Mehdi, the company’s corporate VP and consumer chief marketing officer, wrote in today’s announcement. “If you’ve used the new Bing preview at any time in the last five weeks, you’ve already experienced an early version of this powerful model.”