getStatusCode Deprecation

In CodeIgniter\HTTP\ResponseInterface the getStatusCode function is deprecated and says, "To be replaced by the PSR-7 version (compatible)". I am curious as to why this was deprecated since it is part of the ResponseInterface in the PSR 7 spec found at https://www.php-fig.org/psr/psr-7/. If this should be deprecated, what should we be using as an alternative function to get the status code?