diff --git a/.travis.yml b/.travis.yml
index 51c642e80..66d814eca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -24,7 +24,7 @@ before_install:
   - if [ "$SYMFONY_VERSION" != "" ]; then jq "(.require, .\"require-dev\")|=(with_entries(if .key|test(\"^symfony/\") then .value|=\"${SYMFONY_VERSION}\" else . end))" composer.json|ex -sc 'wq!composer.json' /dev/stdin; fi;
 
 install:
-  - travis_retry composer update -n --prefer-dist
+  - COMPOSER_MEMORY_LIMIT=-1 travis_retry composer update -n --prefer-dist
 
 script:
   - ./vendor/bin/phpunit -v
@@ -34,7 +34,7 @@ jobs:
     - php: 5.5
       env: deps=low SYMFONY_DEPRECATIONS_HELPER=weak
       install:
-        - travis_retry composer update -n --prefer-lowest --prefer-stable --prefer-dist
+        - COMPOSER_MEMORY_LIMIT=-1 travis_retry composer update -n --prefer-lowest --prefer-stable --prefer-dist
 
     - php: 5.6
       env: SYMFONY_VERSION="2.8.*"
diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 57bc50416..0cc7ade25 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -111,8 +111,14 @@ private function addDbalSection(ArrayNodeDefinition $node)
      */
     private function getDbalConnectionsNode()
     {
-        $treeBuilder = new TreeBuilder();
-        $node        = $treeBuilder->root('connections');
+        $treeBuilder = new TreeBuilder('connections');
+
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $node = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $node = $treeBuilder->root('connections');
+        }
 
         /** @var ArrayNodeDefinition $connectionNode */
         $connectionNode = $node
@@ -362,8 +368,14 @@ private function addOrmSection(ArrayNodeDefinition $node)
      */
     private function getOrmTargetEntityResolverNode()
     {
-        $treeBuilder = new TreeBuilder();
-        $node        = $treeBuilder->root('resolve_target_entities');
+        $treeBuilder = new TreeBuilder('resolve_target_entities');
+
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $node = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $node = $treeBuilder->root('resolve_target_entities');
+        }
 
         $node
             ->useAttributeAsKey('interface')
@@ -381,8 +393,15 @@ private function getOrmTargetEntityResolverNode()
      */
     private function getOrmEntityListenersNode()
     {
-        $builder    = new TreeBuilder();
-        $node       = $builder->root('entity_listeners');
+        $treeBuilder = new TreeBuilder('entity_listeners');
+
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $node = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $node = $treeBuilder->root('entity_listeners');
+        }
+
         $normalizer = static function ($mappings) {
             $entities = [];
 
@@ -466,8 +485,14 @@ private function getOrmEntityListenersNode()
      */
     private function getOrmEntityManagersNode()
     {
-        $treeBuilder = new TreeBuilder();
-        $node        = $treeBuilder->root('entity_managers');
+        $treeBuilder = new TreeBuilder('entity_managers');
+
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $node = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $node = $treeBuilder->root('entity_managers');
+        }
 
         $node
             ->requiresAtLeastOneElement()
@@ -630,8 +655,14 @@ private function getOrmEntityManagersNode()
      */
     private function getOrmCacheDriverNode($name)
     {
-        $treeBuilder = new TreeBuilder();
-        $node        = $treeBuilder->root($name);
+        $treeBuilder = new TreeBuilder($name);
+
+        if (method_exists($treeBuilder, 'getRootNode')) {
+            $node = $treeBuilder->getRootNode();
+        } else {
+            // BC layer for symfony/config 4.1 and older
+            $node = $treeBuilder->root($name);
+        }
 
         $node
             ->addDefaultsIfNotSet()
diff --git a/DependencyInjection/DoctrineExtension.php b/DependencyInjection/DoctrineExtension.php
index 11a37483a..d6823008c 100644
--- a/DependencyInjection/DoctrineExtension.php
+++ b/DependencyInjection/DoctrineExtension.php
@@ -801,7 +801,7 @@ protected function loadOrmCacheDrivers(array $entityManager, ContainerBuilder $c
     private function loadPropertyInfoExtractor($entityManagerName, ContainerBuilder $container)
     {
         $propertyExtractorDefinition = $container->register(sprintf('doctrine.orm.%s_entity_manager.property_info_extractor', $entityManagerName), DoctrineExtractor::class);
-        if (class_exists(PropertyInitializableExtractorInterface::class)) {
+        if (interface_exists(PropertyInitializableExtractorInterface::class)) {
             $argumentId = sprintf('doctrine.orm.%s_entity_manager', $entityManagerName);
         } else {
             $argumentId = sprintf('doctrine.orm.%s_entity_manager.metadata_factory', $entityManagerName);
diff --git a/Tests/ContainerTest.php b/Tests/ContainerTest.php
index be5bb3018..5918739c7 100644
--- a/Tests/ContainerTest.php
+++ b/Tests/ContainerTest.php
@@ -3,6 +3,7 @@
 namespace Doctrine\Bundle\DoctrineBundle\Tests;
 
 use Doctrine\DBAL\Types\Type;
+use Symfony\Component\PropertyInfo\PropertyInitializableExtractorInterface;
 
 class ContainerTest extends TestCase
 {
@@ -48,7 +49,9 @@ public function testContainer()
         $this->assertFalse($container->has('doctrine.dbal.default_connection.events.mysqlsessioninit'));
 
         if (interface_exists('Symfony\Component\PropertyInfo\PropertyInfoExtractorInterface') && class_exists('Symfony\Bridge\Doctrine\PropertyInfo\DoctrineExtractor')) {
-            $this->assertInstanceOf('Doctrine\Common\Persistence\Mapping\ClassMetadataFactory', $container->get('doctrine.orm.default_entity_manager.metadata_factory'));
+            if (!interface_exists(PropertyInitializableExtractorInterface::class)) {
+                $this->assertInstanceOf('Doctrine\Common\Persistence\Mapping\ClassMetadataFactory', $container->get('doctrine.orm.default_entity_manager.metadata_factory'));
+            }
             $this->assertInstanceOf('Symfony\Bridge\Doctrine\PropertyInfo\DoctrineExtractor', $container->get('doctrine.orm.default_entity_manager.property_info_extractor'));
         } else {
             $this->assertFalse($container->has('doctrine.orm.default_entity_manager.metadata_factory'));
diff --git a/Tests/ProfilerTest.php b/Tests/ProfilerTest.php
index 89576eb22..158341d2d 100644
--- a/Tests/ProfilerTest.php
+++ b/Tests/ProfilerTest.php
@@ -73,6 +73,9 @@ public function testRender()
         // This is only needed for WebProfilerBundle=3.2, remove when support for it is dropped
         $requestCollector = new RequestDataCollector();
         $requestCollector->collect($request, $response);
+        if (method_exists($requestCollector, 'lateCollect')) {
+            $requestCollector->lateCollect();
+        }
         $profile->addCollector($requestCollector);
 
         $output = $this->twig->render('db.html.twig', [