Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^9.6.13 -> satisfiable by phpunit/phpunit[9.6.13, 9.6.x-dev]. - phpunit/phpunit[9.6.13, ..., 9.6.x-dev] require php >=7.3 -> your php version (7.2.34) does not satisfy that requirement. Problem 2 - phpunit/phpunit[9.6.13, ..., 9.6.x-dev] require php >=7.3 -> your php version (7.2.34) does not satisfy that requirement. - yoast/phpunit-polyfills[1.1.0, ..., 1.x-dev] require phpunit/phpunit ^4.8.36 || ^5.7.21 || ^6.0 || ^7.0 || ^8.0 || ^9.0 -> satisfiable by phpunit/phpunit[9.6.13, 9.6.x-dev]. - Root composer.json requires yoast/phpunit-polyfills ^1.1 -> satisfiable by yoast/phpunit-polyfills[1.1.0, 1.x-dev].