英語のWikipediaがどれぐらい当てになるかわからないが

https://en.wikipedia.org/wiki/Raspberry_Pi

>The Raspberry Pi 4 Model B was released in June 2019
(中略)
> In mid-2021, Pi 4 B models appeared with the improved Broadcom BCM2711C0.
> The manufacturer is now using this chip for the Pi 4 B and Pi 400.