Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires symfony/console ^7.0.1 -> satisfiable by symfony/console[v7.0.1]. - symfony/console v7.0.1 requires php >=8.2 -> your php version (8.1.26) does not satisfy that requirement. Problem 2 - vimeo/psalm[5.4.0, ..., 5.15.0] require symfony/console ^4.1.6 || ^5.0 || ^6.0 -> found symfony/console[v4.1.6, ..., v4.4.49, v5.0.0, ..., v5.4.32, v6.0.0, ..., v6.4.1] but it conflicts with your root composer.json require (^7.0.1). - symfony/console v7.0.1 requires php >=8.2 -> your php version (8.1.26) does not satisfy that requirement. - psalm/plugin-phpunit 0.18.4 requires vimeo/psalm dev-master || dev-4.x || ^4.7.1 || ^5@beta || ^5.0 -> satisfiable by vimeo/psalm[5.4.0, ..., 5.17.0]. - vimeo/psalm[5.16.0, ..., 5.17.0] require symfony/console ^4.1.6 || ^5.0 || ^6.0 || ^7.0 -> satisfiable by symfony/console[v7.0.1]. - Root composer.json requires psalm/plugin-phpunit ^0.18.4 -> satisfiable by psalm/plugin-phpunit[0.18.4]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.