diff --git a/src/PimcoreElementManagerBundle/DependencyInjection/PimcoreElementManagerExtension.php b/src/PimcoreElementManagerBundle/DependencyInjection/PimcoreElementManagerExtension.php
index cc21220..d0c5975 100644
--- a/src/PimcoreElementManagerBundle/DependencyInjection/PimcoreElementManagerExtension.php
+++ b/src/PimcoreElementManagerBundle/DependencyInjection/PimcoreElementManagerExtension.php
@@ -68,13 +68,9 @@ public function load(array $configs, ContainerBuilder $container): void
         );
 
         $bundles = $container->getParameter('kernel.bundles');
+        $isMergeSupported = \array_key_exists('ObjectMergerBundle', $bundles);
 
-        if (\array_key_exists('ObjectMergerBundle', $bundles)) {
-            $container->setParameter('pimcore_element_manager.merge_supported', true);
-        }
-        else {
-            $container->setParameter('pimcore_element_manager.merge_supported', false);
-        }
+        $container->setParameter('pimcore_element_manager.merge_supported', $isMergeSupported);
 
         $this->registerDuplicationCheckerConfiguration($config['duplication'] ?? [], $container, $loader);
 
@@ -105,12 +101,12 @@ private function registerSaveManagerConfiguration(
 
         $definition = new Definition($config['save_manager_class']);
         $options = [
-            'naming_scheme' => $config['naming_scheme']['options'],
-            'duplicates' => $config['duplicates']['options'],
-            'validations' => $config['validations']['options'],
+            'naming_scheme' => $config['naming_scheme']['options'] ?? null,
+            'duplicates' => $config['duplicates']['options'] ?? null,
+            'validations' => $config['validations']['options'] ?? null,
         ];
 
-        if ($config['naming_scheme']['enabled']) {
+        if (isset($config['naming_scheme']['enabled']) && $config['naming_scheme']['enabled'] === true) {
             $namingDefinition = new Definition(NamingSchemeSaveHandler::class, [
                 new Reference($config['naming_scheme']['service']),
             ]);
@@ -126,22 +122,20 @@ private function registerSaveManagerConfiguration(
             ]);
         }
 
-        if ($config['unique_key']['enabled']) {
+        if (isset($config['unique_key']['enabled']) && $config['unique_key']['enabled'] === true) {
             $definition->addMethodCall('addSaveHandler', [new Reference(UniqueKeySaveHandler::class)]);
         }
 
-        if ($config['validations']['enabled_on_save']) {
+        if (isset($config['validations']['enabled_on_save']) && $config['validations']['enabled_on_save'] === true) {
             $definition->addMethodCall('addSaveHandler', [new Reference(ValidationSaveHandler::class)]);
         }
 
-        if ($config['duplicates']['enabled_on_save']) {
+        if (isset($config['duplicates']['enabled_on_save']) && $config['duplicates']['enabled_on_save'] === true) {
             $definition->addMethodCall('addSaveHandler', [new Reference(DuplicationSaveHandler::class)]);
         }
 
-        if ($config['save_handlers']) {
-            foreach ($config['save_handlers'] as $saveHandler) {
-                $definition->addMethodCall('addSaveHandler', [new Reference($saveHandler)]);
-            }
+        foreach ($config['save_handlers'] ?? [] as $saveHandler) {
+            $definition->addMethodCall('addSaveHandler', [new Reference($saveHandler)]);
         }
 
         $definition->addMethodCall('setOptions', [$options]);
@@ -221,9 +215,7 @@ private function registerDuplicationCheckerMapping(ContainerBuilder $container,
             $this->registerMappingFilesFromDir($dir, $fileRecorder);
         }
 
-        if (isset($config['mapping']['paths']) && \is_array($config['mapping']['paths'])) {
-            $this->registerMappingFilesFromConfig($container, $config, $fileRecorder);
-        }
+        $this->registerMappingFilesFromConfig($container, $config, $fileRecorder);
     }
 
     private function registerMappingFilesFromDir($dir, callable $fileRecorder): void
@@ -246,7 +238,7 @@ private function registerMappingFilesFromConfig(
         array $config,
         callable $fileRecorder
     ): void {
-        foreach ($config['mapping']['paths'] as $path) {
+        foreach ($config['mapping']['paths'] ?? [] as $path) {
             if (\is_dir($path)) {
                 $this->registerMappingFilesFromDir($path, $fileRecorder);
                 $container->addResource(new DirectoryResource($path, '/^$/'));
@@ -256,6 +248,7 @@ private function registerMappingFilesFromConfig(
                         \sprintf('Unsupported mapping type in "%s", supported types is only Yaml.', $path)
                     );
                 }
+
                 $fileRecorder($matches[1], $path);
             } else {
                 throw new \RuntimeException(\sprintf('Could not open file or directory "%s".', $path));
@@ -268,16 +261,16 @@ private function registerDuplicateIndexConfiguration(
         string $className,
         array $config
     ): void {
-        if (!$config || !$config['enabled']) {
+        if (!isset($config['enabled']) || $config['enabled'] !== true) {
             return;
         }
 
         $groups = [];
 
-        foreach ($config['groups'] as $groupName => $group) {
+        foreach ($config['groups'] ?? [] as $groupName => $group) {
             $fields = [];
 
-            foreach ($group['fields'] as $fieldName => $fieldConfig) {
+            foreach ($group['fields'] ?? [] as $fieldName => $fieldConfig) {
                 $fieldMetaData = new Definition(FieldMetadata::class, [
                     $fieldName, $fieldConfig,
                 ]);
@@ -312,7 +305,7 @@ private function registerDuplicateIndexConfiguration(
             return;
         }
 
-        $listFields = $config['list_fields'];
+        $listFields = $config['list_fields'] ?? [];
 
         $metadata = new Definition(Metadata::class, [$className, $groups, $listFields]);