diff --git a/src/Kunstmaan/AdminBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/AdminBundle/DependencyInjection/Configuration.php
index d9d30404e0..4ad0b3f750 100644
--- a/src/Kunstmaan/AdminBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/AdminBundle/DependencyInjection/Configuration.php
@@ -20,8 +20,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_admin');
+        $treeBuilder = new TreeBuilder('kunstmaan_admin');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_admin');
+        }
 
         $rootNode
             ->fixXmlConfig('admin_locale')
diff --git a/src/Kunstmaan/AdminListBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/AdminListBundle/DependencyInjection/Configuration.php
index d66d753ce1..06e6bfa70e 100644
--- a/src/Kunstmaan/AdminListBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/AdminListBundle/DependencyInjection/Configuration.php
@@ -17,11 +17,16 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $root = $treeBuilder->root('kunstmaan_k_admin_list');
+        $treeBuilder = new TreeBuilder('kunstmaan_k_admin_list');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_k_admin_list');
+        }
 
         /* @var ArrayNodeDefinition $pages */
-        $root
+        $rootNode
             ->children()
                 ->arrayNode('lock')
                     ->addDefaultsIfNotSet()
diff --git a/src/Kunstmaan/ArticleBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/ArticleBundle/DependencyInjection/Configuration.php
index bdd2bcd0ce..faa01d7b5e 100644
--- a/src/Kunstmaan/ArticleBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/ArticleBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_article');
+        $treeBuilder = new TreeBuilder('kunstmaan_article');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_article');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/ConfigBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/ConfigBundle/DependencyInjection/Configuration.php
index 0a75e5fa6f..fb74b5d6e4 100644
--- a/src/Kunstmaan/ConfigBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/ConfigBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_config');
+        $treeBuilder = new TreeBuilder('kunstmaan_config');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_config');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/DashboardBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/DashboardBundle/DependencyInjection/Configuration.php
index 7ffba01c49..e78896bed2 100644
--- a/src/Kunstmaan/DashboardBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/DashboardBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_dashboard');
+        $treeBuilder = new TreeBuilder('kunstmaan_dashboard');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_dashboard');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/FixturesBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/FixturesBundle/DependencyInjection/Configuration.php
index 675ff7d0aa..812356e378 100644
--- a/src/Kunstmaan/FixturesBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/FixturesBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_fixtures');
+        $treeBuilder = new TreeBuilder('kunstmaan_fixtures');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_fixtures');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/FormBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/FormBundle/DependencyInjection/Configuration.php
index 665dd2f9d3..e8ea4e2c66 100644
--- a/src/Kunstmaan/FormBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/FormBundle/DependencyInjection/Configuration.php
@@ -19,10 +19,14 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_form');
+        $treeBuilder = new TreeBuilder('kunstmaan_form');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_form');
+        }
 
-        $rootNode = $treeBuilder->root('kunstmaan_form');
         $rootNode
             ->children()
                 ->booleanNode('deletable_formsubmissions')->defaultFalse()->end()
diff --git a/src/Kunstmaan/LeadGenerationBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/LeadGenerationBundle/DependencyInjection/Configuration.php
index 0da5063cb0..11f7940900 100644
--- a/src/Kunstmaan/LeadGenerationBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/LeadGenerationBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_lead_generation');
+        $treeBuilder = new TreeBuilder('kunstmaan_lead_generation');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_lead_generation');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/MediaBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/MediaBundle/DependencyInjection/Configuration.php
index 48f9a588da..2ff5b008af 100644
--- a/src/Kunstmaan/MediaBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/MediaBundle/DependencyInjection/Configuration.php
@@ -20,8 +20,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_media');
+        $treeBuilder = new TreeBuilder('kunstmaan_media');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_media');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/MediaPagePartBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/MediaPagePartBundle/DependencyInjection/Configuration.php
index f11a7d1943..df0d2f084e 100644
--- a/src/Kunstmaan/MediaPagePartBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/MediaPagePartBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_media_page_part');
+        $treeBuilder = new TreeBuilder('kunstmaan_media_page_part');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_media_page_part');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/MenuBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/MenuBundle/DependencyInjection/Configuration.php
index 0d692833d1..8468e5a019 100644
--- a/src/Kunstmaan/MenuBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/MenuBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_menu');
+        $treeBuilder = new TreeBuilder('kunstmaan_menu');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_menu');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/MultiDomainBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/MultiDomainBundle/DependencyInjection/Configuration.php
index ab6af8b79d..ff00302bdd 100644
--- a/src/Kunstmaan/MultiDomainBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/MultiDomainBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_multi_domain');
+        $treeBuilder = new TreeBuilder('kunstmaan_multi_domain');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_multi_domain');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/NodeBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/NodeBundle/DependencyInjection/Configuration.php
index 625a0a9c83..6c6b7fa685 100644
--- a/src/Kunstmaan/NodeBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/NodeBundle/DependencyInjection/Configuration.php
@@ -18,11 +18,16 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $root = $treeBuilder->root('kunstmaan_node');
+        $treeBuilder = new TreeBuilder('kunstmaan_node');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_node');
+        }
 
         /* @var ArrayNodeDefinition $pages */
-        $root
+        $rootNode
             ->children()
                 ->arrayNode('pages')
                     ->prototype('array')
diff --git a/src/Kunstmaan/NodeSearchBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/NodeSearchBundle/DependencyInjection/Configuration.php
index 14ddda5c86..ab4faa4f27 100644
--- a/src/Kunstmaan/NodeSearchBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/NodeSearchBundle/DependencyInjection/Configuration.php
@@ -33,8 +33,13 @@ public function __construct($useElasticSearchVersion6)
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_node_search');
+        $treeBuilder = new TreeBuilder('kunstmaan_node_search');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_node_search');
+        }
 
         $rootNode->children()->booleanNode('enable_update_listener')->defaultTrue();
         $rootNode->children()->booleanNode('use_match_query_for_title')->defaultFalse();
diff --git a/src/Kunstmaan/PagePartBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/PagePartBundle/DependencyInjection/Configuration.php
index 9140b54058..450dd16a5d 100644
--- a/src/Kunstmaan/PagePartBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/PagePartBundle/DependencyInjection/Configuration.php
@@ -19,15 +19,21 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $root = $treeBuilder->root('kunstmaan_page_part');
-        $root->children()
+        $treeBuilder = new TreeBuilder('kunstmaan_page_part');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_page_part');
+        }
+
+        $rootNode->children()
             ->booleanNode('extended_pagepart_chooser')
                 ->defaultFalse()
             ->end();
 
         /** @var ArrayNodeDefinition $pageparts */
-        $pageparts = $root->children()->arrayNode('pageparts')->useAttributeAsKey('index')->prototype('array');
+        $pageparts = $rootNode->children()->arrayNode('pageparts')->useAttributeAsKey('index')->prototype('array');
         $pageparts->children()->scalarNode('name')->isRequired();
         $pageparts->children()->scalarNode('context')->isRequired();
         $pageparts->children()->scalarNode('extends');
@@ -43,7 +49,7 @@ public function getConfigTreeBuilder()
         // *************************************************************************************************************
 
         /** @var ArrayNodeDefinition $pagetemplates */
-        $pagetemplates = $root->children()->arrayNode('pagetemplates')->useAttributeAsKey('index')->defaultValue([])->prototype('array');
+        $pagetemplates = $rootNode->children()->arrayNode('pagetemplates')->useAttributeAsKey('index')->defaultValue([])->prototype('array');
 
         $pagetemplates->children()->scalarNode('template')->isRequired();
         $pagetemplates->children()->scalarNode('name')->isRequired();
diff --git a/src/Kunstmaan/RedirectBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/RedirectBundle/DependencyInjection/Configuration.php
index 998a3a098e..68afb50629 100644
--- a/src/Kunstmaan/RedirectBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/RedirectBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_redirect');
+        $treeBuilder = new TreeBuilder('kunstmaan_redirect');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_redirect');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/SearchBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/SearchBundle/DependencyInjection/Configuration.php
index a52e0ee880..6f7c41cfd2 100644
--- a/src/Kunstmaan/SearchBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/SearchBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_search');
+        $treeBuilder = new TreeBuilder('kunstmaan_search');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_search');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/SeoBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/SeoBundle/DependencyInjection/Configuration.php
index 67491e8a6e..6bf91ae69c 100644
--- a/src/Kunstmaan/SeoBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/SeoBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_seo');
+        $treeBuilder = new TreeBuilder('kunstmaan_seo');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_seo');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/SitemapBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/SitemapBundle/DependencyInjection/Configuration.php
index 27dc6755b7..fffb1820f7 100644
--- a/src/Kunstmaan/SitemapBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/SitemapBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_sitemap');
+        $treeBuilder = new TreeBuilder('kunstmaan_sitemap');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_sitemap');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/TaggingBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/TaggingBundle/DependencyInjection/Configuration.php
index 586f86e443..76c436e021 100644
--- a/src/Kunstmaan/TaggingBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/TaggingBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_tagging');
+        $treeBuilder = new TreeBuilder('kunstmaan_tagging');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_tagging');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/TranslatorBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/TranslatorBundle/DependencyInjection/Configuration.php
index 767ed22037..7af0315e2a 100644
--- a/src/Kunstmaan/TranslatorBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/TranslatorBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kuma_translator');
+        $treeBuilder = new TreeBuilder('kuma_translator');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kuma_translator');
+        }
 
         $availableStorageEngines = array('orm');
         $defaultFileFormats = array('yml', 'xliff');
diff --git a/src/Kunstmaan/UserManagementBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/UserManagementBundle/DependencyInjection/Configuration.php
index 496e99606f..b936e1abb3 100644
--- a/src/Kunstmaan/UserManagementBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/UserManagementBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $treeBuilder->root('kunstmaan_user_management');
+        $treeBuilder = new TreeBuilder('kunstmaan_user_management');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_user_management');
+        }
 
         // Here you should define the parameters that are allowed to
         // configure your bundle. See the documentation linked above for
diff --git a/src/Kunstmaan/UtilitiesBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/UtilitiesBundle/DependencyInjection/Configuration.php
index 1670bf5dd4..4fc279deda 100644
--- a/src/Kunstmaan/UtilitiesBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/UtilitiesBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_utilities');
+        $treeBuilder = new TreeBuilder('kunstmaan_utilities');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_utilities');
+        }
 
         $rootNode
             ->children()
diff --git a/src/Kunstmaan/VotingBundle/DependencyInjection/Configuration.php b/src/Kunstmaan/VotingBundle/DependencyInjection/Configuration.php
index 90760b11a2..c7fe6b819e 100644
--- a/src/Kunstmaan/VotingBundle/DependencyInjection/Configuration.php
+++ b/src/Kunstmaan/VotingBundle/DependencyInjection/Configuration.php
@@ -17,8 +17,13 @@ class Configuration implements ConfigurationInterface
      */
     public function getConfigTreeBuilder()
     {
-        $treeBuilder = new TreeBuilder();
-        $rootNode = $treeBuilder->root('kunstmaan_voting');
+        $treeBuilder = new TreeBuilder('kunstmaan_voting');
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $rootNode = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $rootNode = $treeBuilder->root('kunstmaan_voting');
+        }
 
         $rootNode
             ->children()