Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^11.0 -> satisfiable by phpunit/phpunit[11.5.50, ..., 11.5.55]. - Root composer.json requires vimeo/psalm ^5.0 -> satisfiable by vimeo/psalm[5.0.0, ..., 5.26.1]. - phpunit/php-code-coverage 11.0.12 requires nikic/php-parser ^5.7.0 -> satisfiable by nikic/php-parser[v5.7.0]. - phpunit/phpunit 11.5.50 requires phpunit/php-code-coverage ^11.0.12 -> satisfiable by phpunit/php-code-coverage[11.0.12]. - phpunit/phpunit 11.5.50 requires sebastian/diff ^6.0.2 -> satisfiable by sebastian/diff[6.0.2]. - sebastian/diff[4.0.0, ..., 4.0.1] require php ^7.3 -> your php version (8.2.30) does not satisfy that requirement. - vimeo/psalm[5.0.0, ..., 5.4.0] require sebastian/diff ^4.0 -> satisfiable by sebastian/diff[4.0.0, ..., 4.0.6]. - vimeo/psalm[5.5.0, ..., 5.21.1] require sebastian/diff ^4.0 || ^5.0 -> satisfiable by sebastian/diff[4.0.0, ..., 4.0.6, 5.0.0, ..., 5.1.1]. - vimeo/psalm[5.22.0, ..., 5.25.0] require nikic/php-parser ^4.16 -> satisfiable by nikic/php-parser[v4.16.0, ..., v4.19.5]. - vimeo/psalm[5.26.0, ..., 5.26.1] require nikic/php-parser ^4.17 -> satisfiable by nikic/php-parser[v4.17.0, ..., v4.19.5]. - Conclusion: don't install phpunit/phpunit 11.5.55 (conflict analysis result) - You can only install one version of a package, so only one of these can be installed: nikic/php-parser[v4.13.0, ..., v4.19.5, v5.0.0, ..., v5.7.0]. - You can only install one version of a package, so only one of these can be installed: sebastian/diff[4.0.0, ..., 4.0.6, 5.0.0, ..., 5.1.1, 6.0.0, 6.0.1, 6.0.2, 7.0.0, 8.0.0].