Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpstan/phpstan ^1.11 -> satisfiable by phpstan/phpstan[1.11.0, 1.11.1, 1.11.2, 1.11.3]. - phpstan/phpstan[1.11.0, ..., 1.11.3] require php ^7.2|^8.0 -> your php version (7.1.33) does not satisfy that requirement. Problem 2 - friendsofphp/php-cs-fixer[v3.53.0, ..., v3.58.1] require php ^7.4 || ^8.0 -> your php version (7.1.33) does not satisfy that requirement. - Root composer.json requires friendsofphp/php-cs-fixer ^3.53 -> satisfiable by friendsofphp/php-cs-fixer[v3.53.0, ..., v3.58.1].