Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires roave/backward-compatibility-check ^8.10.0 -> satisfiable by roave/backward-compatibility-check[8.10.0, 8.11.0]. - Root composer.json requires vimeo/psalm ^6.4.0 -> satisfiable by vimeo/psalm[6.4.0]. - roave/backward-compatibility-check[8.10.0, ..., 8.11.0] require nikic/php-parser ^4.19.1 -> satisfiable by nikic/php-parser[v4.19.1, v4.19.2, v4.19.3, v4.19.4]. - vimeo/psalm 6.4.0 requires nikic/php-parser ^5.0.0 -> satisfiable by nikic/php-parser[v5.0.0, ..., v5.4.0]. - You can only install one version of a package, so only one of these can be installed: nikic/php-parser[v4.15.1, ..., v4.19.4, v5.3.0, v5.3.1, v5.4.0]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.