diff --git a/core/modules/aggregator/aggregator.install b/core/modules/aggregator/aggregator.install
index a763639..aab9ea5 100644
--- a/core/modules/aggregator/aggregator.install
+++ b/core/modules/aggregator/aggregator.install
@@ -37,3 +37,16 @@ function aggregator_update_8001() {
 /**
  * @} End of "addtogroup updates-8.0.0-rc".
  */
+
+/**
+ * Promote 'guid' field to uuid entity key.
+ */
+function aggregator_update_8002() {
+  $manager = \Drupal::entityDefinitionUpdateManager();
+  $entity_type = $manager->getEntityType('aggregator_item');
+  $entity_keys = $entity_type->getKeys();
+  $entity_keys['uuid'] = 'guid';
+  $entity_type->set('entity_keys', $entity_keys);
+  $manager->updateEntityType($entity_type);
+  $manager->updateFieldStorageDefinition($manager->getFieldStorageDefinition('guid', 'aggregator_item'));
+}
diff --git a/core/modules/aggregator/src/Tests/AggregatorTitleTest.php b/core/modules/aggregator/src/Tests/AggregatorTitleTest.php
index d599d9a..cea30fd 100644
--- a/core/modules/aggregator/src/Tests/AggregatorTitleTest.php
+++ b/core/modules/aggregator/src/Tests/AggregatorTitleTest.php
@@ -54,6 +54,7 @@ public function testStringFormatter() {
     $aggregator_feed = Feed::create([
       'title' => 'testing title',
       'url' => 'http://www.example.com',
+      'guid' => $this->randomMachineName(),
     ]);
     $aggregator_feed->save();
 
@@ -62,6 +63,7 @@ public function testStringFormatter() {
       'title' => 'test title',
       'fid' => $aggregator_feed->id(),
       'link' => 'http://www.example.com',
+      'guid' => $this->randomMachineName(),
       ]);
     $aggregator_item->save();
 
diff --git a/core/modules/aggregator/src/Tests/Views/AggregatorItemViewsFieldAccessTest.php b/core/modules/aggregator/src/Tests/Views/AggregatorItemViewsFieldAccessTest.php
index b1c23c5..b020131 100644
--- a/core/modules/aggregator/src/Tests/Views/AggregatorItemViewsFieldAccessTest.php
+++ b/core/modules/aggregator/src/Tests/Views/AggregatorItemViewsFieldAccessTest.php
@@ -40,12 +40,14 @@ public function testAggregatorItemFields() {
     $feed = Feed::create([
       'title' => 'Drupal org',
       'url' => 'https://www.drupal.org/rss.xml',
+      'guid' => $this->randomMachineName(),
     ]);
     $feed->save();
     $item = Item::create([
       'title' => 'Test title',
       'fid' => $feed->id(),
       'description' => 'Test description',
+      'guid' => $this->randomMachineName(),
     ]);
 
     $item->save();
diff --git a/core/modules/aggregator/src/Tests/Views/IntegrationTest.php b/core/modules/aggregator/src/Tests/Views/IntegrationTest.php
index 51665b2..89b6a2d 100644
--- a/core/modules/aggregator/src/Tests/Views/IntegrationTest.php
+++ b/core/modules/aggregator/src/Tests/Views/IntegrationTest.php
@@ -91,7 +91,7 @@ public function testAggregatorItemView() {
       // Add a image to ensure that the sanitizing can be tested below.
       $values['author'] = $this->randomMachineName() . '<img src="http://example.com/example.png" \>"';
       $values['link'] = 'https://www.drupal.org/node/' . mt_rand(1000, 10000);
-      $values['guid'] = $i;
+      $values['guid'] = 'guid-' . $i;
 
       $aggregator_item = $this->itemStorage->create($values);
       $aggregator_item->save();
diff --git a/core/modules/aggregator/tests/modules/aggregator_test_views/test_views/views.view.test_aggregator_items.yml b/core/modules/aggregator/tests/modules/aggregator_test_views/test_views/views.view.test_aggregator_items.yml
index 653bc49..6776ef2 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test_views/test_views/views.view.test_aggregator_items.yml
+++ b/core/modules/aggregator/tests/modules/aggregator_test_views/test_views/views.view.test_aggregator_items.yml
@@ -192,7 +192,7 @@ display:
           admin_label: ''
           empty: false
           tokenize: true
-          target: 1
+          target: guid-1
           view_mode: default
           bypass_access: true
           plugin_id: entity