Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit[11.0.0, ..., 11.2.5] require php >=8.2 -> your php version (8.1.28) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^11 -> satisfiable by phpunit/phpunit[11.0.0, ..., 11.2.5].