I recently upgrade eight PHP Katas from a minimum PHP 7.3 to a minimum of PHP 8.0. I used Rector, Easy Coding Standard (ECS) and PhpStan to help me. This is how I approached the upgrade and used these tools.
Note: This is my standard setup from 2020, a newer version from 2021 is now available Standard setup for PHP projects 2021. The focus of this post if to setup PHP and PhpStorm in a consistant way for each project, with coding standards, static analysis and tests.