Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit[9.6.0, ..., 9.6.23] require php >=7.3 -> your php version (7.0.33) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^9.6 -> satisfiable by phpunit/phpunit[9.6.0, ..., 9.6.23].