Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires php ^8.3 but your php version (7.2.34) does not satisfy that requirement. Problem 2 - Root composer.json requires phpunit/phpunit ^9.5 -> satisfiable by phpunit/phpunit[9.5.0, ..., 9.6.23]. - phpunit/phpunit[9.5.0, ..., 9.6.23] require php >=7.3 -> your php version (7.2.34) does not satisfy that requirement.