Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpspec/prophecy ^1.20 -> satisfiable by phpspec/prophecy[v1.20.0]. - Root composer.json requires phpunit/phpunit ^12 -> satisfiable by phpunit/phpunit[12.0.0, 12.0.1]. - phpspec/prophecy v1.20.0 requires sebastian/comparator ^3.0 || ^4.0 || ^5.0 || ^6.0 -> satisfiable by sebastian/comparator[3.0.0, ..., 3.0.5, 4.0.0, ..., 4.0.8, 5.0.0, 5.0.1, 5.0.2, 5.0.3, 6.0.0, ..., 6.3.0]. - phpunit/phpunit[12.0.0, ..., 12.0.1] require sebastian/comparator ^7.0.0 -> satisfiable by sebastian/comparator[7.0.0]. - sebastian/comparator[3.0.0, ..., 3.0.2] require php ^7.1 -> your php version (8.3.16) does not satisfy that requirement. - sebastian/comparator[4.0.0, ..., 4.0.2] require php ^7.3 -> your php version (8.3.16) does not satisfy that requirement. - You can only install one version of a package, so only one of these can be installed: sebastian/comparator[3.0.0, ..., 3.0.5, 4.0.0, ..., 4.0.8, 5.0.0, 5.0.1, 5.0.2, 5.0.3, 6.0.0, ..., 6.3.0, 7.0.0].