diff --git a/core/lib/Drupal/Core/Serialization/XmlEncoder.php b/core/lib/Drupal/Core/Serialization/XmlEncoder.php
index 1d0dbde..7235af3 100644
--- a/core/lib/Drupal/Core/Serialization/XmlEncoder.php
+++ b/core/lib/Drupal/Core/Serialization/XmlEncoder.php
@@ -25,7 +25,7 @@ class XmlEncoder extends SerializerAwareEncoder implements EncoderInterface, Dec
    *
    * @var array
    */
-  static protected $format = 'xml';
+  static protected $format = array('xml');
 
   /**
    * An instance of the Symfony XmlEncoder to perform the actual encoding.
@@ -50,10 +50,10 @@ public function encode($data, $format){
   }
 
   /**
-   * Implements \Symfony\Component\Serializer\Encoder\JsonEncoder::supportEncoding().
+   * Implements \Symfony\Component\Serializer\Encoder\JsonEncoder::supportsEncoding().
    */
   public function supportsEncoding($format) {
-    return $format === static::$format;
+    return in_array($format, static::$format);
   }
 
   /**
@@ -64,9 +64,9 @@ public function decode($data, $format){
   }
 
   /**
-   * Implements \Symfony\Component\Serializer\Encoder\JsonEncoder::supportDecoding().
+   * Implements \Symfony\Component\Serializer\Encoder\JsonEncoder::supportsDecoding().
    */
   public function supportsDecoding($format) {
-    return $format === static::$format;
+    return in_array($format, static::$format);
   }
 }