Fatal error: Uncaught Error: Interface 'Composer\Plugin\PluginInterface' not found in /var/www/alldocs/home/sdoehner/webtest/simplesamlphp_idp/vendor/simplesamlphp/composer-module-installer/src/SimpleSamlPhp/Composer/ModuleInstallerPlugin.php:9 Stack trace: #0 {main} thrown in /var/www/alldocs/home/sdoehner/webtest/simplesamlphp_idp/vendor/simplesamlphp/composer-module-installer/src/SimpleSamlPhp/Composer/ModuleInstallerPlugin.php on line 9