Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^12.0 -> satisfiable by phpunit/phpunit[12.0.0, 12.0.x-dev]. - phpunit/phpunit[12.0.0, ..., 12.0.x-dev] require php >=8.3 -> your php version (8.1.31) does not satisfy that requirement. Problem 2 - Root composer.json requires symfony/config ^7.0 -> satisfiable by symfony/config[v7.0.0-BETA1, ..., 7.3.x-dev]. - symfony/config[v7.0.0-BETA1, ..., 7.3.x-dev] require php >=8.2 -> your php version (8.1.31) does not satisfy that requirement.