Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^13.0.0 -> satisfiable by phpunit/phpunit[13.0.0, ..., 13.1.7]. - phpunit/phpunit[13.0.0, ..., 13.1.7] require php >=8.4.1 -> your php version (8.3.26) does not satisfy that requirement. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.