* The parameter `regex` has been deprecated and replaced by `pattern`.
    * You can read more about it in the docs for [Query Parameters and String Validations: Add regular expressions](https://fastapi.tiangolo.com/tutorial/query-params-str-validations/#add-regular-expressions).
* New Pydantic models use an improved and simplified attribute `model_config` that takes a simple dict instead of an internal class `Config` for their configuration.