Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires simplesamlphp/simplesamlphp ^2.3 -> satisfiable by simplesamlphp/simplesamlphp[v2.3.0, v2.3.1, v2.3.2]. - simplesamlphp/simplesamlphp[v2.3.0, ..., v2.3.2] require simplesamlphp/saml2 ^4.6 -> found simplesamlphp/saml2[v4.6.0, ..., v4.6.12] but it conflicts with your root composer.json require (^5@dev).