Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires nette/phpstan-rules ^1.0 -> satisfiable by nette/phpstan-rules[1.0.x-dev (alias of dev-master)]. - nette/phpstan-rules dev-master requires php 8.1 - 8.5 -> your php version (8.0.30) does not satisfy that requirement. - nette/phpstan-rules 1.0.x-dev is an alias of nette/phpstan-rules dev-master and thus requires it to be installed too.