Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpcsstandards/phpcsdevcs ^1.1.6 -> satisfiable by phpcsstandards/phpcsdevcs[1.1.6]. - phpcsstandards/phpcsdevcs 1.1.6 requires squizlabs/php_codesniffer ^3.6.2 -> found squizlabs/php_codesniffer[dev-master, 3.6.2, ..., 3.x-dev (alias of dev-master)] but it conflicts with your root composer.json require (4.x-dev). Problem 2 - Root composer.json requires phpcsstandards/phpcsutils ^1.0 -> satisfiable by phpcsstandards/phpcsutils[1.0.0-alpha1, ..., 1.x-dev]. - phpcsstandards/phpcsutils[1.0.0-alpha1, ..., 1.0.0-alpha2] require squizlabs/php_codesniffer ^2.6.0 || ^3.1.0 -> found squizlabs/php_codesniffer[dev-master, 2.6.0, ..., 2.9.x-dev, 3.1.0, ..., 3.x-dev (alias of dev-master)] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils 1.0.0-alpha3 requires squizlabs/php_codesniffer ^2.6.0 || ^3.1.0 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 2.6.0, ..., 2.9.x-dev, 3.1.0, ..., 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils[1.0.0-alpha4, ..., 1.0.8] require squizlabs/php_codesniffer ^3.7.1 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 3.7.1, ..., 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils[1.0.10, ..., 1.0.11] require squizlabs/php_codesniffer ^3.9.0 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 3.9.0, ..., 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils[1.0.12, ..., 1.x-dev] require squizlabs/php_codesniffer ^3.10.0 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 3.10.0, ..., 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils 1.0.9 requires squizlabs/php_codesniffer ^3.8.0 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 3.8.0, ..., 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils dev-develop requires squizlabs/php_codesniffer ^3.13.0 || 4.0.x-dev@dev -> found squizlabs/php_codesniffer[dev-master, 3.13.0, 3.x-dev (alias of dev-master), 4.0.x-dev] but it conflicts with your root composer.json require (4.x-dev). - phpcsstandards/phpcsutils 1.x-dev is an alias of phpcsstandards/phpcsutils dev-develop and thus requires it to be installed too.