diff --git a/core/modules/entity/lib/Drupal/entity/DatabaseStorageController.php b/core/modules/entity/lib/Drupal/entity/DatabaseStorageController.php
index 37c7a24..cbf1a53 100644
--- a/core/modules/entity/lib/Drupal/entity/DatabaseStorageController.php
+++ b/core/modules/entity/lib/Drupal/entity/DatabaseStorageController.php
@@ -504,7 +504,7 @@ class DatabaseStorageController implements EntityStorageControllerInterface {
    */
   protected function invokeHook($hook, EntityInterface $entity, EntityInterface $original = NULL) {
     if (!empty($this->entityInfo['fieldable']) && function_exists($function = 'field_attach_' . $hook)) {
-      $function($this->entityType, $entity);
+      $function($this->entityType, $entity, $original);
     }
     // Invoke the hook.
     module_invoke_all($this->entityType . '_' . $hook, $entity, $original);
diff --git a/core/modules/field/field.api.php b/core/modules/field/field.api.php
index 455ecc2..7b5edb9 100644
--- a/core/modules/field/field.api.php
+++ b/core/modules/field/field.api.php
@@ -480,7 +480,7 @@ function hook_field_insert($entity_type, $entity, $field, $instance, $langcode,
  *
  * @param $entity_type
  *   The type of $entity.
- * @param $entity
+ * @param Drupal\entity\EntityInterface $entity
  *   The entity for the operation.
  * @param $field
  *   The field structure for the operation.
@@ -490,11 +490,13 @@ function hook_field_insert($entity_type, $entity, $field, $instance, $langcode,
  *   The language associated with $items.
  * @param $items
  *   $entity->{$field['field_name']}[$langcode], or an empty array if unset.
+ * @param Drupal\entity\EntityInterface $original
+ *   The original entity, or NULL if the caller did not provide it.
  *
  * @see hook_field_insert()
  * @see hook_field_delete()
  */
-function hook_field_update($entity_type, $entity, $field, $instance, $langcode, &$items) {
+function hook_field_update($entity_type, Drupal\entity\EntityInterface $entity, $field, $instance, $langcode, &$items, Drupal\entity\EntityInterface $original = NULL) {
   if (variable_get('taxonomy_maintain_index_table', TRUE) && $field['storage']['type'] == 'field_sql_storage' && $entity_type == 'node') {
     $first_call = &drupal_static(__FUNCTION__, array());
 
diff --git a/core/modules/field/field.attach.inc b/core/modules/field/field.attach.inc
index e4b28a9..122272d 100644
--- a/core/modules/field/field.attach.inc
+++ b/core/modules/field/field.attach.inc
@@ -5,6 +5,7 @@
  * Field attach API, allowing entities (nodes, users, ...) to be 'fieldable'.
  */
 
+use Drupal\entity\EntityInterface;
 use Drupal\field\FieldValidationException;
 
 /**
@@ -127,6 +128,7 @@ const FIELD_STORAGE_INSERT = 'insert';
  * @param $a
  *   - The $form in the 'form' operation.
  *   - The value of $view_mode in the 'view' operation.
+ *   - The original entity in the 'update' operation. May be NULL.
  *   - Otherwise NULL.
  * @param $b
  *   - The $form_state in the 'submit' operation.
@@ -929,11 +931,13 @@ function field_attach_insert($entity_type, $entity) {
  *
  * @param $entity_type
  *   The type of $entity; e.g. 'node' or 'user'.
- * @param $entity
+ * @param EntityInterface $entity
  *   The entity with fields to save.
+ * @param EntityInterface $original
+ *   The original entity. May be NULL.
  */
-function field_attach_update($entity_type, $entity) {
-  _field_invoke('update', $entity_type, $entity);
+function field_attach_update($entity_type, EntityInterface $entity, EntityInterface $original = NULL) {
+  _field_invoke('update', $entity_type, $entity, $original);
 
   list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
 
diff --git a/core/modules/file/file.field.inc b/core/modules/file/file.field.inc
index 768ee7d..d7c2dc7 100644
--- a/core/modules/file/file.field.inc
+++ b/core/modules/file/file.field.inc
@@ -1,5 +1,7 @@
 <?php
 
+use Drupal\entity\EntityInterface;
+
 /**
  * @file
  * Field module functionality for the File module.
@@ -241,7 +243,7 @@ function file_field_insert($entity_type, $entity, $field, $instance, $langcode,
  *
  * Checks for files that have been removed from the object.
  */
-function file_field_update($entity_type, $entity, $field, $instance, $langcode, &$items) {
+function file_field_update($entity_type, EntityInterface $entity, $field, $instance, $langcode, &$items, EntityInterface $original = NULL) {
   list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
 
   // On new revisions, all files are considered to be a new usage and no
@@ -260,7 +262,6 @@ function file_field_update($entity_type, $entity, $field, $instance, $langcode,
   }
 
   // Compare the original field values with the ones that are being saved.
-  $original = $entity->original;
   $original_fids = array();
   if (!empty($original->{$field['field_name']}[$langcode])) {
     foreach ($original->{$field['field_name']}[$langcode] as $original_item) {
diff --git a/core/modules/image/image.field.inc b/core/modules/image/image.field.inc
index 2a32c15..de30e30 100644
--- a/core/modules/image/image.field.inc
+++ b/core/modules/image/image.field.inc
@@ -1,5 +1,7 @@
 <?php
 
+use Drupal\entity\EntityInterface;
+
 /**
  * @file
  * Implement an image field, based on the file module's file field.
@@ -243,7 +245,7 @@ function image_field_insert($entity_type, $entity, $field, $instance, $langcode,
 /**
  * Implements hook_field_update().
  */
-function image_field_update($entity_type, $entity, $field, $instance, $langcode, &$items) {
+function image_field_update($entity_type, EntityInterface $entity, $field, $instance, $langcode, &$items, EntityInterface $original = NULL) {
   file_field_update($entity_type, $entity, $field, $instance, $langcode, $items);
 }
 
diff --git a/core/modules/node/lib/Drupal/node/NodeStorageController.php b/core/modules/node/lib/Drupal/node/NodeStorageController.php
index 3bd871b..6d18396 100644
--- a/core/modules/node/lib/Drupal/node/NodeStorageController.php
+++ b/core/modules/node/lib/Drupal/node/NodeStorageController.php
@@ -205,9 +205,13 @@ class NodeStorageController extends DatabaseStorageController {
    * Overrides Drupal\entity\DatabaseStorageController::invokeHook().
    */
   protected function invokeHook($hook, EntityInterface $node, EntityInterface $original = NULL) {
-    if ($hook == 'insert' || $hook == 'update') {
+    if ($hook == 'insert') {
       node_invoke($node, $hook);
     }
+    elseif ($hook == 'update') {
+      // Core does not use $original on update, but contrib might.
+      node_invoke($node, $hook, $original);
+    }
     else if ($hook == 'predelete') {
       // 'delete' is triggered in 'predelete' is here to preserve hook ordering
       // from Drupal 7.
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 287c5af..7b29f6c 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -935,6 +935,7 @@ function node_hook($node, $hook) {
  *   A string containing the name of the hook.
  * @param $a2, $a3, $a4
  *   Arguments to pass on to the hook, after the $node argument.
+ *   - If $op = 'update': $a2 is the original node.
  *
  * @return
  *   The returned value of the invoked hook.