Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires chevere/action ^1.0.x-dev -> satisfiable by chevere/action[1.0.x-dev]. - chevere/action 1.0.x-dev requires chevere/parameter ^1.0.x-dev -> found chevere/parameter[1.0.x-dev] but it does not match your minimum-stability. Problem 2 - Root composer.json requires chevere/var-dump ^0.10.x-dev -> satisfiable by chevere/var-dump[0.10.x-dev]. - chevere/var-dump 0.10.x-dev requires chevere/parameter ^1.0.x-dev -> found chevere/parameter[1.0.x-dev] but it does not match your minimum-stability.