diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 3630e7ba..6e0671f5 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -26,8 +26,15 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder(): TreeBuilder
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('liip_functional_test', 'array');
+        if (method_exists(TreeBuilder::class, 'getRootNode')) {
+            $treeBuilder = new TreeBuilder('liip_functional_test');
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $treeBuilder = new TreeBuilder();
+            $rootNode = $treeBuilder->root('liip_functional_test', 'array');
+        }
+
         $rootNode
             ->children()
                 ->arrayNode('cache_db')