Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires maplephp/unitary ^2.0 -> satisfiable by maplephp/unitary[v2.0.0, ..., v2.1.0]. - maplephp/unitary[v2.0.0, ..., v2.1.0] require maplephp/validate ^2.0 -> satisfiable by maplephp/validate[dev-main, dev-develop, v2.0.0, v2.0.1, 2.x-dev (alias of dev-main)] from composer repo (https://repo.packagist.org) but maplephp/validate dev-54950ca71e63205378e2dc949238e1d0b3f7284f is the root package and cannot be modified. See https://getcomposer.org/dep-on-root for details and assistance.