Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit 11.4.x -> satisfiable by phpunit/phpunit[11.4.0, 11.4.x-dev (alias of dev-main)]. - phpunit/phpunit dev-main requires php >=8.2 -> your php version (8.1.30) does not satisfy that requirement. - phpunit/phpunit 11.4.x-dev is an alias of phpunit/phpunit dev-main and thus requires it to be installed too.