Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires simplesamlphp/xml-common ~3.0 -> satisfiable by simplesamlphp/xml-common[v3.0.0]. - simplesamlphp/xml-common v3.0.0 requires simplesamlphp/assert ~3.0 -> found simplesamlphp/assert[v3.0.0] but it conflicts with your root composer.json require (~2.0). Problem 2 - Root composer.json requires simplesamlphp/xml-security ~3.0 -> satisfiable by simplesamlphp/xml-security[v3.0.0]. - simplesamlphp/xml-security v3.0.0 requires simplesamlphp/assert ~3.0 -> found simplesamlphp/assert[v3.0.0] but it conflicts with your root composer.json require (~2.0). Problem 3 - Root composer.json requires simplesamlphp/xml-soap ~3.0 -> satisfiable by simplesamlphp/xml-soap[v3.0.0]. - simplesamlphp/xml-soap v3.0.0 requires simplesamlphp/assert ~3.0 -> found simplesamlphp/assert[v3.0.0] but it conflicts with your root composer.json require (~2.0). Problem 4 - Root composer.json requires simplesamlphp/simplesamlphp ^2.5 -> satisfiable by simplesamlphp/simplesamlphp[v2.5.2]. - simplesamlphp/simplesamlphp v2.5.2 requires simplesamlphp/saml2 ~6.1 -> satisfiable by simplesamlphp/saml2[dev-master, v6.1.0, ..., v6.2.3] from composer repo (https://repo.packagist.org) but simplesamlphp/saml2 dev-release-7.x is the root package and cannot be modified. See https://getcomposer.org/dep-on-root for details and assistance.