Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit[10.0.0, ..., 10.2.6] require php >=8.1 -> your php version (8.0.29) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^10.0.0 -> satisfiable by phpunit/phpunit[10.0.0, ..., 10.2.6]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.