diff --git a/src/Update/UpdateHelper.php b/src/Update/UpdateHelper.php
new file mode 100644
index 0000000..f6dfdae
--- /dev/null
+++ b/src/Update/UpdateHelper.php
@@ -0,0 +1,122 @@
+<?php
+
+namespace Drupal\workbench_email\Update;
+
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\workbench_email\TemplateInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines a class for update helpers.
+ */
+class UpdateHelper implements ContainerInjectionInterface {
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * ConfigEntityUpdater constructor.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager.
+   */
+  public function __construct(EntityTypeManagerInterface $entity_type_manager) {
+    $this->entityTypeManager = $entity_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('entity_type.manager')
+    );
+  }
+
+  /**
+   * Update helper for migrating from old configuration to recipient plugins.
+   *
+   * @param \Drupal\workbench_email\TemplateInterface $template
+   *   Template being updated.
+   *
+   * @return bool
+   *   TRUE if updates were made.
+   */
+  public static function updateToRecipientPlugin(TemplateInterface $template) {
+    $plugins = [];
+    if ($template->get('author')) {
+      $plugins['author'] = [
+        'id' => 'author',
+        'provider' => 'workbench_email',
+        'status' => TRUE,
+        'settings' => [],
+      ];
+    }
+    if ($roles = $template->get('roles')) {
+      $plugins['role'] = [
+        'id' => 'role',
+        'provider' => 'workbench_email',
+        'status' => TRUE,
+        'settings' => [
+          'roles' => $roles,
+        ],
+      ];
+    }
+    if ($fields = $template->get('fields')) {
+      $plugins['email'] = [
+        'id' => 'email',
+        'provider' => 'workbench_email',
+        'status' => TRUE,
+        'settings' => [
+          'fields' => $fields,
+        ],
+      ];
+    }
+    $template->set('recipient_types', $plugins);
+    $template->set('fields', NULL);
+    $template->set('roles', NULL);
+    $template->set('author', NULL);
+    return TRUE;
+  }
+
+  /**
+   * Updates template entities in Drupal core < 8.6.
+   *
+   * @param array $sandbox
+   *   Stores information for batch updates.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *   When the entity type is not found.
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   *   When the entity type is not found.
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   *   If an error occurs during update.
+   *
+   * @see workbench_email_post_update_move_to_recipient_plugins()
+   */
+  public function legacyUpdateToRecipientPlugin(array &$sandbox) {
+    $storage = $this->entityTypeManager->getStorage('workbench_email_template');
+    $sandbox_key = 'config_entity_updater:workbench_email_template';
+    if (!isset($sandbox[$sandbox_key])) {
+      $sandbox[$sandbox_key]['entities'] = $storage->getQuery()->accessCheck(FALSE)->execute();
+      $sandbox[$sandbox_key]['count'] = count($sandbox[$sandbox_key]['entities']);
+    }
+
+    /** @var \Drupal\workbench_email\TemplateInterface $template */
+    $entities = $storage->loadMultiple(array_splice($sandbox[$sandbox_key]['entities'], 0, 50));
+    foreach ($entities as $template) {
+      if (self::updateToRecipientPlugin($template)) {
+        $template->trustData();
+        $template->save();
+      }
+    }
+
+    $sandbox['#finished'] = empty($sandbox[$sandbox_key]['entities']) ? 1 : ($sandbox[$sandbox_key]['count'] - count($sandbox[$sandbox_key]['entities'])) / $sandbox[$sandbox_key]['count'];
+  }
+
+}
diff --git a/workbench_email.post_update.php b/workbench_email.post_update.php
index 05ca4b1..1a91a84 100644
--- a/workbench_email.post_update.php
+++ b/workbench_email.post_update.php
@@ -7,45 +7,17 @@
 
 use Drupal\Core\Config\Entity\ConfigEntityUpdater;
 use Drupal\workbench_email\TemplateInterface;
+use Drupal\workbench_email\Update\UpdateHelper;
 
 /**
  * Updates config entities to use the new recipient plugins.
  */
 function workbench_email_post_update_move_to_recipient_plugins(&$sandbox = NULL) {
-  \Drupal::classResolver(ConfigEntityUpdater::class)->update($sandbox, 'workbench_email_template', function (TemplateInterface $template) {
-    $plugins = [];
-    if ($template->get('author')) {
-      $plugins['author'] = [
-        'id' => 'author',
-        'provider' => 'workbench_email',
-        'status' => TRUE,
-        'settings' => [],
-      ];
-    }
-    if ($roles = $template->get('roles')) {
-      $plugins['role'] = [
-        'id' => 'role',
-        'provider' => 'workbench_email',
-        'status' => TRUE,
-        'settings' => [
-          'roles' => $roles,
-        ],
-      ];
-    }
-    if ($fields = $template->get('fields')) {
-      $plugins['email'] = [
-        'id' => 'email',
-        'provider' => 'workbench_email',
-        'status' => TRUE,
-        'settings' => [
-          'fields' => $fields,
-        ],
-      ];
-    }
-    $template->set('recipient_types', $plugins);
-    $template->set('fields', NULL);
-    $template->set('roles', NULL);
-    $template->set('author', NULL);
-    return TRUE;
-  });
+  if (class_exists(ConfigEntityUpdater::class)) {
+    \Drupal::classResolver(ConfigEntityUpdater::class)
+      ->update($sandbox, 'workbench_email_template', [UpdateHelper::class, 'updateToRecipientPlugin']);
+    return;
+  }
+  // Drupal core < 8.6, no config entity updater.
+  \Drupal::classResolver()->getInstanceFromDefinition(UpdateHelper::class)->legacyUpdateToRecipientPlugin($sandbox);
 }