diff --git a/flag.install b/flag.install
index a98a3ad..7eae2da 100644
--- a/flag.install
+++ b/flag.install
@@ -5,8 +5,12 @@
  * Flag module install/schema/update hooks.
  */
 
+use Drupal\Core\Database\Database;
 use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Config\Entity\ConfigEntityStorage;
+use Drupal\Core\Extension\MissingDependencyException;
+use Drupal\Core\Utility\UpdateException;
+use Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem;
 
 /**
  * Implements hook_schema().
@@ -103,3 +107,49 @@ function flag_requirements($phase) {
   */
   return $requirements;
 }
+
+/**
+ * Update flagging table to use dynamic_entity_reference.
+ */
+function flag_update_8001() {
+  if (!\Drupal::moduleHandler()->moduleExists('dynamic_entity_reference')) {
+    try {
+      /** @var \Drupal\Core\Extension\ModuleInstallerInterface $installer */
+      $installer = \Drupal::service('module_installer');
+      $installer->install(['dynamic_entity_reference']);
+    }
+    catch (MissingDependencyException $e) {
+      throw new UpdateException('The dynamic_entity_reference module could not be found. Please download and rerun database updates.', $e->getCode(), $e);
+    }
+  }
+
+  // Previous schema was `entity_type` and `entity_id`. New schema is
+  // `flagged_entity__target_type` and `flagged_entity__target_id`.
+  // @see \Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem::schema()
+  $spec = [
+    'description' => 'The Entity Type ID of the target entity.',
+    'type' => 'varchar_ascii',
+    'length' => EntityTypeInterface::BUNDLE_MAX_LENGTH,
+  ];
+  Database::getConnection()->schema()->changeField('flagging', 'entity_type', 'flagged_entity__target_type', $spec);
+
+  $spec = [
+    'description' => 'The ID of the target entity.',
+    'type' => 'varchar_ascii',
+    'length' => 255,
+  ];
+  $keys = [
+    'target_id' => ['flagged_entity__target_id', 'flagged_entity__target_type'],
+  ];
+  Database::getConnection()->schema()->changeField('flagging', 'entity_id', 'flagged_entity__target_id', $spec, $keys);
+
+  /** @var \Drupal\dynamic_entity_reference\Storage\IntColumnHandlerInterface $int_column_handler */
+  $int_column_handler = \Drupal::service('dynamic_entity_reference.storage.create_column');
+  // Adds the integer column.
+  $int_column_handler->create('flagging', ['flagged_entity__target_id']);
+
+  // Populate the int column.
+  Database::getConnection()->update('flagging')
+    ->expression('flagged_entity__target_id_int', 'flagged_entity__target_id')
+    ->execute();
+}