diff --git a/Resources/config/mongodb.xml b/Resources/config/mongodb.xml
index 8e15533..398a0ca 100644
--- a/Resources/config/mongodb.xml
+++ b/Resources/config/mongodb.xml
@@ -26,7 +26,7 @@
             <argument type="collection" /> <!-- events -->
             <argument type="service" id="fos_elastica.indexable" />
             <argument type="collection" /> <!-- configuration -->
-            <argument /> <!-- logger -->
+            <argument>null</argument> <!-- logger -->
         </service>
 
         <service id="fos_elastica.elastica_to_model_transformer.prototype.mongodb" class="%fos_elastica.elastica_to_model_transformer.prototype.mongodb.class%" public="false" abstract="true">
diff --git a/Resources/config/orm.xml b/Resources/config/orm.xml
index d78ae8d..554bd3e 100644
--- a/Resources/config/orm.xml
+++ b/Resources/config/orm.xml
@@ -25,7 +25,7 @@
             <argument type="collection" /> <!-- events -->
             <argument type="service" id="fos_elastica.indexable" />
             <argument type="collection" /> <!-- configuration -->
-            <argument on-invalid="ignore" /> <!-- logger -->
+            <argument>null</argument> <!-- logger -->
         </service>
 
         <service id="fos_elastica.elastica_to_model_transformer.prototype.orm" class="%fos_elastica.elastica_to_model_transformer.prototype.orm.class%" public="false" abstract="true">