Your requirements could not be resolved to an installable set of packages. Problem 1 - vimeo/psalm[5.17.0, ..., 5.x-dev] require sebastian/diff ^4.0 || ^5.0 -> satisfiable by sebastian/diff[4.0.0, ..., 4.0.x-dev, 5.0.0, ..., 5.1.x-dev]. - You can only install one version of a package, so only one of these can be installed: sebastian/diff[4.0.0, ..., 4.0.x-dev, 5.0.0, ..., 5.1.x-dev, 6.0.0, 6.0.x-dev]. - phpunit/phpunit[11.0.0, ..., 11.0.x-dev] require sebastian/diff ^6.0 -> satisfiable by sebastian/diff[6.0.0, 6.0.x-dev]. - sebastian/diff[4.0.0, ..., 4.0.1] require php ^7.3 -> your php version (8.2.14) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^11.0 -> satisfiable by phpunit/phpunit[11.0.0, 11.0.x-dev]. - Root composer.json requires vimeo/psalm ^5.17 -> satisfiable by vimeo/psalm[5.17.0, ..., 5.x-dev].