Your requirements could not be resolved to an installable set of packages. Problem 1 - vimeo/psalm[4.8.1, ..., 4.30.0] require sebastian/diff ^3.0 || ^4.0 -> satisfiable by sebastian/diff[3.0.0, ..., 3.0.4, 4.0.0, ..., 4.0.5]. - You can only install one version of a package, so only one of these can be installed: sebastian/diff[3.0.2, 3.0.3, 3.0.4, 4.0.0, ..., 4.0.5, 5.0.0, 5.0.1, 5.0.2, 5.0.3]. - phpunit/phpunit 10.3.0 requires sebastian/diff ^5.0 -> satisfiable by sebastian/diff[5.0.0, 5.0.1, 5.0.2, 5.0.3]. - Root composer.json requires phpunit/phpunit ^10.3.0 -> satisfiable by phpunit/phpunit[10.3.0]. - Root composer.json requires vimeo/psalm ^4.8.1 -> satisfiable by vimeo/psalm[4.8.1, ..., 4.30.0]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.