Your requirements could not be resolved to an installable set of packages. Problem 1 - nettrine/orm dev-master requires nettrine/dbal ^0.8.0 || ^0.9.0 -> satisfiable by nettrine/dbal[dev-master, v0.8.0, v0.8.1, v0.8.2, 0.9.x-dev (alias of dev-master)] from composer repo (https://repo.packagist.org) but nettrine/dbal is the root package and cannot be modified. See https://getcomposer.org/dep-on-root for details and assistance. - nettrine/orm 0.9.x-dev is an alias of nettrine/orm dev-master and thus requires it to be installed too. - Root composer.json requires nettrine/orm ^0.9.0 -> satisfiable by nettrine/orm[0.9.x-dev (alias of dev-master)].