diff -u b/core/modules/update/src/Controller/UpdateController.php b/core/modules/update/src/Controller/UpdateController.php
--- b/core/modules/update/src/Controller/UpdateController.php
+++ b/core/modules/update/src/Controller/UpdateController.php
@@ -3,7 +3,6 @@
 namespace Drupal\update\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
-use Drupal\Core\Render\RendererInterface;
 use Drupal\update\UpdateFetcherInterface;
 use Drupal\update\UpdateManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -21,27 +20,13 @@
   protected $updateManager;
 
   /**
-   * The renderer.
-   *
-   * @var \Drupal\Core\Render\RendererInterface
-   */
-  protected $renderer;
-
-  /**
    * Constructs update status data.
    *
    * @param \Drupal\update\UpdateManagerInterface $update_manager
    *   Update Manager Service.
-   * @param \Drupal\Core\Render\RendererInterface|null $renderer
-   *   The renderer.
    */
-  public function __construct(UpdateManagerInterface $update_manager, RendererInterface $renderer = NULL) {
+  public function __construct(UpdateManagerInterface $update_manager) {
     $this->updateManager = $update_manager;
-    if (is_null($renderer)) {
-      @trigger_error('The renderer service should be passed to UpdateController::__construct() since 9.1.0. This will be required in Drupal 10.0.0. See https://www.drupal.org/node/3179315', E_USER_DEPRECATED);
-      $renderer = \Drupal::service('renderer');
-    }
-    $this->renderer = $renderer;
   }
 
   /**
@@ -49,8 +34,7 @@
    */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('update.manager'),
-      $container->get('renderer')
+      $container->get('update.manager')
     );
   }
 
@@ -78,8 +62,7 @@
         }
       }
       if ($fetch_failed) {
-        $message = ['#theme' => 'update_fetch_error_message'];
-        $this->messenger()->addError($this->renderer->renderPlain($message));
+        $this->messenger()->addError(['#theme' => 'update_fetch_error_message']);
       }
     }
     return $build;
diff -u b/core/modules/update/src/Form/UpdateManagerUpdate.php b/core/modules/update/src/Form/UpdateManagerUpdate.php
--- b/core/modules/update/src/Form/UpdateManagerUpdate.php
+++ b/core/modules/update/src/Form/UpdateManagerUpdate.php
@@ -252,8 +252,7 @@
     }
 
     if ($fetch_failed) {
-      $message = ['#theme' => 'update_fetch_error_message'];
-      $this->messenger()->addError(\Drupal::service('renderer')->renderPlain($message));
+      $this->messenger()->addError(['#theme' => 'update_fetch_error_message']);
     }
 
     if (empty($projects)) {
diff -u b/core/modules/update/src/UpdateFetcher.php b/core/modules/update/src/UpdateFetcher.php
--- b/core/modules/update/src/UpdateFetcher.php
+++ b/core/modules/update/src/UpdateFetcher.php
@@ -63,7 +63,7 @@
     $this->httpClient = $http_client;
     $this->updateSettings = $config_factory->get('update.settings');
     if (is_null($settings)) {
-      @trigger_error('The settings service should be passed to UpdateFetcherr::__construct() since 9.1.0. This will be required in Drupal 10.0.0. See https://www.drupal.org/node/3179315', E_USER_DEPRECATED);
+      @trigger_error('The settings service should be passed to UpdateFetcher::__construct() since 9.1.0. This will be required in Drupal 10.0.0. See https://www.drupal.org/node/3179315', E_USER_DEPRECATED);
       $settings = \Drupal::service('settings');
     }
     $this->withHttpFallback = $settings->get('update_fetch_with_http_fallback', FALSE);
@@ -93,7 +93,7 @@
    * @return string
    *   The body of the HTTP(S) request, or an empty string on failure.
    */
-  protected function doRequest(string $url, array $options, bool $with_http_fallback) : string {
+  protected function doRequest(string $url, array $options, bool $with_http_fallback): string {
     $data = '';
     try {
       $data = (string) $this->httpClient
diff -u b/core/modules/update/tests/src/Unit/UpdateFetcherTest.php b/core/modules/update/tests/src/Unit/UpdateFetcherTest.php
--- b/core/modules/update/tests/src/Unit/UpdateFetcherTest.php
+++ b/core/modules/update/tests/src/Unit/UpdateFetcherTest.php
@@ -167,7 +167,7 @@
     // First, try without the HTTP fallback setting, and HTTPS mocked to fail.
     $settings = new Settings([]);
     $this->mockClient(
-      new Response('500', [], 'https failed'),
+      new Response('500', [], 'HTTPS failed'),
     );
     $update_fetcher = new UpdateFetcher($this->mockConfigFactory, $this->mockHttpClient, $settings);
 
@@ -176,7 +176,7 @@
     $this->assertCount(1, $this->history);
     $request = $this->history[0]['request'];
     $this->assertNotEmpty($request);
-    // It should have only been an https request.
+    // It should have only been an HTTPS request.
     $this->assertEquals('https', $request->getUri()->getScheme());
     // And it should have failed.
     $response = $this->history[0]['response'];
@@ -191,8 +191,8 @@
   public function testUpdateFetcherHttpFallback() {
     $settings = new Settings(['update_fetch_with_http_fallback' => TRUE]);
     $this->mockClient(
-      new Response('500', [], 'https failed'),
-      new Response('200', [], 'http worked'),
+      new Response('500', [], 'HTTPS failed'),
+      new Response('200', [], 'HTTP worked'),
     );
     $update_fetcher = new UpdateFetcher($this->mockConfigFactory, $this->mockHttpClient, $settings);
 
@@ -201,20 +201,20 @@
     // There should be two request / response pairs.
     $this->assertCount(2, $this->history);
 
-    // The first should have been https and should have failed.
+    // The first should have been HTTPS and should have failed.
     $first_try = $this->history[0];
     $this->assertNotEmpty($first_try);
     $this->assertEquals('https', $first_try['request']->getUri()->getScheme());
     $this->assertEquals(500, $first_try['response']->getStatusCode());
 
-    // The second should have been the http fallback and should have worked.
+    // The second should have been the HTTP fallback and should have worked.
     $second_try = $this->history[1];
     $this->assertNotEmpty($second_try);
     $this->assertEquals('http', $second_try['request']->getUri()->getScheme());
     $this->assertEquals(200, $second_try['response']->getStatusCode());
     // Although this is a bogus mocked response, it's what fetchProjectData()
     // should return in this case.
-    $this->assertEquals('http worked', $data);
+    $this->assertEquals('HTTP worked', $data);
   }
 
 }