quietone
--- a/core/modules/update/update.module
+++ b/core/modules/update/update.module
+    $subject = t('Security release(s) available for @site_name', ['@site_name' => \Drupal::config('system.site')->get('name'), 'langcode' => $langcode]);
+  }
+
+  // If no subject yet then check for fetch failures. If all the reasons
+  // are fetch failures the use the fetch subject.
+  if (empty($subject)) {
+    $fetch = array_filter($all_reasons, function ($item) {
+      return $item > 0;
+    });
+    if (empty($fetch) && !empty($all_reasons)) {
+      $subject = t('Failed to get release information for @site_name', ['@site_name' => \Drupal::config('system.site')->get('name'), 'langcode' => $langcode]);
+    }
+  }
+
+  // If still no subject, then there are non-security updates and use the non-
+  // security subject. Then update the subject in the existing message.
-  // If still no subject, then there are non-security updates and use the non-
-  // security subject. Then update the subject in the existing message.
+  // If the subject still has not been set, then there are only non-security
+  // updates. Use the subject for non-security updates.
--- a/core/modules/update/update.module
+++ b/core/modules/update/update.module
+  // are fetch failures the use the fetch subject.
+  if (empty($subject)) {
+    $fetch = array_filter($all_reasons, function ($item) {
+      return $item > 0;
+    });
+    if (empty($fetch) && !empty($all_reasons)) {
+      $subject = t('Failed to get release information for @site_name', ['@site_name' => \Drupal::config('system.site')->get('name'), 'langcode' => $langcode]);
+    }
+  }
+
+  // If still no subject, then there are non-security updates and use the non-
+  // security subject. Then update the subject in the existing message.
+  if (empty($subject)) {
+    $subject = t('New release(s) available for @site_name', ['@site_name' => \Drupal::config('system.site')->get('name'), 'langcode' => $langcode]);
+  }
+  $message['subject'] .= $subject;
-  $message['subject'] .= $subject;
+
+  // Update the existing message.
+  $message['subject'] .= $subject;