Your requirements could not be resolved to an installable set of packages. Problem 1 - vimeo/psalm[5.22.0, ..., 5.22.1] require nikic/php-parser ^4.16 -> satisfiable by nikic/php-parser[v4.16.0, v4.17.0, v4.17.1, v4.18.0]. - You can only install one version of a package, so only one of these can be installed: nikic/php-parser[v4.0.0, ..., v4.18.0, v5.0.0]. - vimeo/psalm[5.16.0, ..., 5.21.1] require sebastian/diff ^4.0 || ^5.0 -> satisfiable by sebastian/diff[4.0.0, ..., 4.0.5, 5.0.0, ..., 5.1.0]. - phpunit/php-code-coverage 11.0.0 requires nikic/php-parser ^5.0 -> satisfiable by nikic/php-parser[v5.0.0]. - You can only install one version of a package, so only one of these can be installed: sebastian/diff[4.0.0, ..., 4.0.5, 5.0.0, ..., 5.1.0, 6.0.0]. - phpunit/phpunit[11.0.0, ..., 11.0.3] require phpunit/php-code-coverage ^11.0 -> satisfiable by phpunit/php-code-coverage[11.0.0]. - phpunit/phpunit[11.0.0, ..., 11.0.3] require sebastian/diff ^6.0 -> satisfiable by sebastian/diff[6.0.0]. - sebastian/diff[4.0.0, ..., 4.0.1] require php ^7.3 -> your php version (8.3.2) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^11.0 -> satisfiable by phpunit/phpunit[11.0.0, 11.0.1, 11.0.2, 11.0.3]. - Root composer.json requires vimeo/psalm ^5.16 -> satisfiable by vimeo/psalm[5.16.0, ..., 5.22.1]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.