Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires symfony/cache ^7.2.3 -> satisfiable by symfony/cache[v7.2.3]. - symfony/cache v7.2.3 requires php >=8.2 -> your php version (8.1.31) does not satisfy that requirement. Problem 2 - Root composer.json requires phpunit/phpunit ^12 -> satisfiable by phpunit/phpunit[12.0.0, 12.0.1, 12.0.2, 12.0.3]. - phpunit/phpunit[12.0.0, ..., 12.0.3] require php >=8.3 -> your php version (8.1.31) does not satisfy that requirement.