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/emitron ^1.0 -> satisfiable by maplephp/emitron[dev-main, dev-develop, v1.0.0, v1.0.1, v1.1.0, 1.x-dev (alias of dev-main)] from composer repo (https://repo.packagist.org) but maplephp/emitron 2.x-dev is the root package and cannot be modified. See https://getcomposer.org/dep-on-root for details and assistance.