diff --git a/core/modules/user/src/AccountForm.php b/core/modules/user/src/AccountForm.php
index 03e808f978..77c67a0600 100644
--- a/core/modules/user/src/AccountForm.php
+++ b/core/modules/user/src/AccountForm.php
@@ -392,7 +392,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
         _user_mail_notify('mail_change_notification', $account);
         // The user's mail address will be updated only after verification.
         $form_state->setValue('mail', $old_mail);
-        $this->messenger->addWarning($this->t('Your updated email address needs to be validated. Further instructions have been sent to your new email address.'));
+        $this->messenger()->addWarning($this->t('Your updated email address needs to be validated. Further instructions have been sent to your new email address.'));
       }
     }
 
diff --git a/core/modules/user/src/Controller/MailChangeController.php b/core/modules/user/src/Controller/MailChangeController.php
index 3084be4403..7f339e82b7 100644
--- a/core/modules/user/src/Controller/MailChangeController.php
+++ b/core/modules/user/src/Controller/MailChangeController.php
@@ -33,6 +33,7 @@ public function page(UserInterface $user, $new_mail, $timestamp, $hash) {
     /** @var \Drupal\Core\Session\AccountProxyInterface $current_user */
     $current_user = $this->currentUser();
     $request_time = \Drupal::time()->getRequestTime();
+    $messenger = $this->messenger();
 
     // Other user is authenticated.
     if ($current_user->isAuthenticated() && $current_user->id() != $user->id()) {
@@ -40,11 +41,11 @@ public function page(UserInterface $user, $new_mail, $timestamp, $hash) {
         '%user' => $current_user->getAccountName(),
         ':logout' => Url::fromRoute('user.logout')->toString(),
       ];
-      $this->messenger->addError($this->t('You are currently logged in as %user, and are attempting to confirm an email address change for another account. Please <a href=":logout">log out</a> and try using the link again.', $arguments));
+      $messenger->addError($this->t('You are currently logged in as %user, and are attempting to confirm an email address change for another account. Please <a href=":logout">log out</a> and try using the link again.', $arguments));
     }
     // The link has expired.
     elseif ($request_time - $timestamp > $timeout) {
-      $this->messenger->addError($this->t('You have tried to use an email address change link that has expired. Please visit your account and change your email again.'));
+      $messenger->addError($this->t('You have tried to use an email address change link that has expired. Please visit your account and change your email again.'));
     }
     // The link is valid.
     elseif ($timestamp <= $request_time && $timestamp >= $user->getLastLoginTime() && Crypt::hashEquals($hash, user_pass_rehash($user, $timestamp, $new_mail))) {
@@ -59,12 +60,12 @@ public function page(UserInterface $user, $new_mail, $timestamp, $hash) {
         $current_user->setAccount($user);
       }
       $arguments = ['%mail' => $new_mail];
-      $this->messenger->addStatus($this->t('Your email address has been changed to %mail.', $arguments));
+      $messenger->addStatus($this->t('Your email address has been changed to %mail.', $arguments));
     }
     // Timestamp from the link is abnormal (in the future) or user registered a
     // new login in the meantime or the hash is not valid.
     else {
-      $this->messenger->addError($this->t('You have tried to use an email address change link that has either been used or is no longer valid. Please visit your account and change your email again.'));
+      $messenger->addError($this->t('You have tried to use an email address change link that has either been used or is no longer valid. Please visit your account and change your email again.'));
     }
 
     return $this->redirect('<front>');
diff --git a/core/modules/user/tests/src/Functional/Update/UpdateMailChangeTest.php b/core/modules/user/tests/src/Functional/Update/UpdateMailChangeTest.php
index b5f8d6ab92..8c05593979 100644
--- a/core/modules/user/tests/src/Functional/Update/UpdateMailChangeTest.php
+++ b/core/modules/user/tests/src/Functional/Update/UpdateMailChangeTest.php
@@ -9,6 +9,7 @@
  * Tests update of user mail change configurations.
  *
  * @group user
+ * @group legacy
  */
 class UpdateMailChangeTest extends UpdatePathTestBase {
 
@@ -17,7 +18,7 @@ class UpdateMailChangeTest extends UpdatePathTestBase {
    */
   protected function setDatabaseDumpFiles() {
     $this->databaseDumpFiles = [
-      __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-8-rc1.bare.standard.php.gz',
+      __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-8.4.0.bare.standard.php.gz',
     ];
   }
 
@@ -48,7 +49,7 @@ public function testMailChangeUpdate() {
     $this->assertFalse($user_settings->get('notify.mail_change_notification'));
     $this->assertFalse($user_settings->get('notify.mail_change_verification'));
 
-    $config = Yaml::parse(file_get_contents(__DIR__ . '/../../../config/install/user.mail.yml'));
+    $config = Yaml::parse(file_get_contents(__DIR__ . '/../../../../config/install/user.mail.yml'));
 
     // Check that mail change configurations were set to default values.
     $this->assertSame($config['mail_change_notification'], $user_mail->get('mail_change_notification'));