diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index c4e09039..2891edff 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -58,11 +58,10 @@ public function getConfigTreeBuilder()
                             ->scalarNode('callback')->isRequired()->end()
                             ->arrayNode('qos_options')
                                 ->canBeUnset()
-                                ->useAttributeAsKey('key')
                                 ->children()
                                     ->scalarNode('prefetch_size')->defaultValue(0)->end()
                                     ->scalarNode('prefetch_count')->defaultValue(0)->end()
-                                    ->booleanNode('global')->defaultValue(false)->end()
+                                    ->booleanNode('global')->defaultFalse()->end()
                                 ->end()
                             ->end()
                         ->end()