Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpcsstandards/phpcsutils ^1.0.9, found phpcsstandards/phpcsutils[dev-stable, dev-develop, 1.x-dev (alias of dev-stable)] but it does not match your minimum-stability. Problem 2 - Root composer.json requires phpcsstandards/phpcsextra ^1.2.1, found phpcsstandards/phpcsextra[dev-stable, dev-develop, 1.x-dev (alias of dev-stable)] but it does not match your minimum-stability. Problem 3 - Root composer.json requires phpcsstandards/phpcsdevtools ^1.2.2, found phpcsstandards/phpcsdevtools[dev-feature-complete/fix-msg-display-order-jumbling, dev-feature/switch-to-fork-of-phpcs, dev-TEST/readme-xsd-workflow, dev-stable, dev-develop, 1.0.0, ..., 1.2.1] but it does not match the constraint. Problem 4 - Root composer.json requires phpcsstandards/php_codesniffer dev-master -> satisfiable by phpcsstandards/php_codesniffer[dev-master]. - phpcompatibility/php-compatibility[9.0.0, ..., 9.3.5] conflict with squizlabs/php_codesniffer 2.6.2 (phpcsstandards/php_codesniffer dev-master replaces squizlabs/php_codesniffer > 2.0). - Root composer.json requires phpcompatibility/php-compatibility ^9.0 -> satisfiable by phpcompatibility/php-compatibility[9.0.0, ..., 9.3.5].