Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires simplesamlphp/simplesamlphp-test-framework ~1.11.5 -> satisfiable by simplesamlphp/simplesamlphp-test-framework[v1.11.5]. - simplesamlphp/simplesamlphp v2.5.0 requires simplesamlphp/saml2 ~6.1 -> satisfiable by simplesamlphp/saml2[dev-master, v6.1.0, ..., 6.1.x-dev (alias of dev-master)] from composer repo (https://repo.packagist.org) but simplesamlphp/saml2 dev-release-6.1 is the root package and cannot be modified. See https://getcomposer.org/dep-on-root for details and assistance. - simplesamlphp/simplesamlphp-test-framework v1.11.5 requires simplesamlphp/simplesamlphp ^2.5 -> satisfiable by simplesamlphp/simplesamlphp[v2.5.0].