Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/phpunit[11.0.0, ..., 11.5.2] require php >=8.2 -> your php version (8.1.31) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^11.0.0 -> satisfiable by phpunit/phpunit[11.0.0, ..., 11.5.2]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.