Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires chiiya/code-style-php ^3.0 -> satisfiable by chiiya/code-style-php[3.0.0, 3.0.1, 3.0.2, 3.0.3]. - chiiya/code-style-php[3.0.0, ..., 3.0.3] require php ^8.2 -> your php version (8.1.29) does not satisfy that requirement. Problem 2 - phpunit/phpunit[dev-main, 11.3.0, ..., 11.3.5] require php >=8.2 -> your php version (8.1.29) does not satisfy that requirement. - phpunit/phpunit 11.4.x-dev is an alias of phpunit/phpunit dev-main and thus requires it to be installed too. - Root composer.json requires phpunit/phpunit ^11.3 -> satisfiable by phpunit/phpunit[11.3.0, ..., 11.4.x-dev (alias of dev-main)].