diff -u b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php
--- b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php
+++ b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php
@@ -49,7 +49,7 @@
    *
    * @return bool
    */
-  public function changed($key) {
+  public function isChanged($key) {
     return $this->config->get($key) !== $this->config->getOriginal($key);
   }
 
diff -u b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php
--- b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php
+++ b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php
@@ -27,8 +27,8 @@
    * @param string $old_name
    *   The old configuration object name.
    */
-  public function __construct(Config $confg, $old_name) {
-    $this->config = $confg;
+  public function __construct(Config $config, $old_name) {
+    $this->config = $config;
     $this->oldName = $old_name;
   }
 
diff -u b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
--- b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
+++ b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
@@ -9,6 +9,7 @@
 
 use Drupal\Component\PhpStorage\PhpStorageFactory;
 use Drupal\Core\Config\ConfigCrudEvent;
+use Drupal\Core\Config\ConfigEvents;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 /**
@@ -24,7 +25,7 @@
    */
   public function onConfigSave(ConfigCrudEvent $event) {
     $saved_config = $event->getConfig();
-    if ($saved_config->getName() == 'system.site' && $event->changed('langcode')) {
+    if ($saved_config->getName() == 'system.site' && $event->isChanged('langcode')) {
       // Trigger a container rebuild on the next request by deleting compiled
       // from PHP storage.
       PhpStorageFactory::get('service_container')->deleteAll();
@@ -35,7 +36,7 @@
    * {@inheritdoc}
    */
   static function getSubscribedEvents() {
-    $events['config.save'][] = array('onConfigSave', 0);
+    $events[ConfigEvents::SAVE][] = array('onConfigSave', 0);
     return $events;
   }