diff --git a/core/modules/forum/src/Controller/ForumController.php b/core/modules/forum/src/Controller/ForumController.php
index 501bfa4425d1eef5ec1af0cba6cee9aeefd4a9d8..347013b812c60d0100884ed197dcf0cdb97f21cf 100644
--- a/core/modules/forum/src/Controller/ForumController.php
+++ b/core/modules/forum/src/Controller/ForumController.php
@@ -154,7 +154,7 @@ public static function create(ContainerInterface $container) {
   public function forumPage(TermInterface $taxonomy_term) {
     // Get forum details.
     $taxonomy_term->forums = $this->forumManager->getChildren($this->config('forum.settings')->get('vocabulary'), $taxonomy_term->id());
-    $taxonomy_term->parents = $this->forumManager->getParents($taxonomy_term->id());
+    $taxonomy_term->parents = $this->termStorage->loadAllParents($taxonomy_term->id());
 
     if (empty($taxonomy_term->forum_container->value)) {
       $build = $this->forumManager->getTopics($taxonomy_term->id(), $this->currentUser());
diff --git a/core/modules/forum/src/ForumManager.php b/core/modules/forum/src/ForumManager.php
index 29e03e1cb7f4ddd2d85a78e49b8b7439d1e32ab6..e8be2869e898d64f574949e1cd247655148620ef 100644
--- a/core/modules/forum/src/ForumManager.php
+++ b/core/modules/forum/src/ForumManager.php
@@ -480,6 +480,7 @@ public function resetCache() {
    * {@inheritdoc}
    */
   public function getParents($tid) {
+    @trigger_error(__NAMESPACE__ . '\ForumManager::getParents() is deprecated in drupal:8.1.0 and is removed from drupal:9.0.0. Call loadAllParents() on taxonomy term storage directly. See https://www.drupal.org/node/3069599', E_USER_DEPRECATED);
     return $this->entityTypeManager->getStorage('taxonomy_term')->loadAllParents($tid);
   }
 
diff --git a/core/modules/forum/src/ForumManagerInterface.php b/core/modules/forum/src/ForumManagerInterface.php
index 9e8833ebcf356c0ed202fa3920f7e8a501bd1086..f1f7079ec5fbc4838010786f1643ff145d686ff3 100644
--- a/core/modules/forum/src/ForumManagerInterface.php
+++ b/core/modules/forum/src/ForumManagerInterface.php
@@ -60,8 +60,10 @@ public function resetCache();
    * @return array
    *   Array of parent terms.
    *
-   * @deprecated Scheduled to be removed in 9.0.x, see
-   *   https://www.drupal.org/node/2371593.
+   * @deprecated in drupal:8.1.0 and is removed from drupal:9.0.0. Call
+   * loadAllParents() on taxonomy term storage directly.
+   *
+   * @see https://www.drupal.org/node/3069599
    */
   public function getParents($tid);
 
diff --git a/core/modules/forum/tests/src/Kernel/LegacyForumTest.php b/core/modules/forum/tests/src/Kernel/LegacyForumTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..fdd610aa26904bbaca5151b331c649472d5229bb
--- /dev/null
+++ b/core/modules/forum/tests/src/Kernel/LegacyForumTest.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Drupal\Tests\forum\Kernel;
+
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests Legacy forum code.
+ *
+ * @group forum
+ * @group legacy
+ */
+class LegacyForumTest extends KernelTestBase {
+
+  protected static $modules = [
+    'comment',
+    'forum',
+    'system',
+    'taxonomy',
+    'text',
+    'user',
+  ];
+
+  /**
+   * The taxonomy term storage.
+   *
+   * @var \Drupal\taxonomy\TermStorage
+   */
+  protected $termStorage;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installEntitySchema('taxonomy_term');
+    $this->installConfig('forum');
+    $this->termStorage = \Drupal::entityTypeManager()->getStorage('taxonomy_term');
+  }
+
+  /**
+   * Tests the getParents() method.
+   *
+   * @expectedDeprecation Drupal\forum\ForumManager::getParents() is deprecated in drupal:8.1.0 and is removed from drupal:9.0.0. Call loadAllParents() on taxonomy term storage directly. See https://www.drupal.org/node/3069599
+   */
+  public function testGetParents() {
+    // Add a forum.
+    $forum = $this->termStorage->create([
+      'name' => 'Forum',
+      'vid' => 'forums',
+      'forum_container' => 1,
+    ]);
+    $forum->save();
+
+    // Add a container.
+    $subforum = $this->termStorage->create([
+      'name' => 'Subforum',
+      'vid' => 'forums',
+      'forum_container' => 0,
+      'parent' => $forum->id(),
+    ]);
+    $subforum->save();
+
+    $legacy_parents = \Drupal::service('forum_manager')->getParents($subforum->id());
+    $parents = $this->termStorage->loadAllParents($subforum->id());
+    $this->assertSame($parents, $legacy_parents);
+  }
+
+}