diff --git a/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php b/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
index 8332745..611e28f 100644
--- a/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
+++ b/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
@@ -25,7 +25,7 @@
  *   }
  * )
  */
-class EntityFormDisplay extends EntityDisplayBase implements EntityFormDisplayInterface, \Serializable {
+class EntityFormDisplay extends EntityDisplayBase implements EntityFormDisplayInterface {
 
   /**
    * {@inheritdoc}
@@ -148,20 +148,20 @@ public function getRenderer($field_name) {
   /**
    * {@inheritdoc}
    */
-  public function serialize() {
+  public function __sleep() {
     // Only store the definition, not external objects or derived data.
-    $data = $this->getExportProperties() + array('entityType' => $this->getEntityTypeId());
-    return serialize($data);
+    $keys = array_keys($this->getExportProperties());
+    $keys[] = 'entityTypeId';
+    return $keys;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function unserialize($serialized) {
-    $data = unserialize($serialized);
-    $entity_type = $data['entityType'];
-    unset($data['entityType']);
-    $this->__construct($data, $entity_type);
+  public function __wakeup() {
+    // Run the values from getExportProperties() through __construct().
+    $values = array_intersect_key($this->getExportProperties(), get_object_vars($this));
+    $this->__construct($values, $this->entityTypeId);
   }
 
 }