diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index 68502c6..9b92879 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -74,7 +74,7 @@ class Config {
    *
    * @var array
    */
-  protected $originalData;
+  protected $originalData = array();
 
   /**
    * The current runtime data.
@@ -457,7 +457,7 @@ public function save() {
 
     $this->storage->write($this->name, $this->data);
     $this->isNew = FALSE;
-    $this->notify('save');
+    $this->eventDispatcher->dispatch(ConfigEvents::SAVE, new ConfigCrudEvent($this));
     $this->originalData = $this->data;
     return $this;
   }
@@ -474,7 +474,7 @@ public function delete() {
     $this->storage->delete($this->name);
     $this->isNew = TRUE;
     $this->resetOverriddenData();
-    $this->notify('delete');
+    $this->eventDispatcher->dispatch(ConfigEvents::DELETE, new ConfigCrudEvent($this));
     $this->originalData = $this->data;
     return $this;
   }
@@ -490,16 +490,6 @@ public function getStorage() {
   }
 
   /**
-   * Dispatches a configuration event.
-   *
-   * @param string $config_event_name
-   *   The configuration event name.
-   */
-  protected function notify($config_event_name) {
-    $this->eventDispatcher->dispatch('config.' . $config_event_name, new ConfigEvent($this));
-  }
-
-  /**
    * Merges data into a configuration object.
    *
    * @param array $data_to_merge
diff --git a/core/lib/Drupal/Core/Config/ConfigCrudEvent.php b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php
new file mode 100644
index 0000000..f7d9b70
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/ConfigCrudEvent.php
@@ -0,0 +1,57 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Config\ConfigCrudEvent.
+ */
+
+namespace Drupal\Core\Config;
+
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Wraps a configuration event for event listeners.
+ */
+class ConfigCrudEvent extends Event {
+
+  /**
+   * Configuration object.
+   *
+   * @var \Drupal\Core\Config\Config
+   */
+  protected $config;
+
+  /**
+   * Constructs a configuration event object.
+   *
+   * @param \Drupal\Core\Config\Config
+   *   Configuration object.
+   */
+  public function __construct(Config $config) {
+    $this->config = $config;
+  }
+
+  /**
+   * Gets configuration object.
+   *
+   * @return \Drupal\Core\Config\Config
+   *   The configuration object that caused the event to fire.
+   */
+  public function getConfig() {
+    return $this->config;
+  }
+
+  /**
+   * Checks to see if the provided configuration key's value has changed.
+   *
+   * @param string $key
+   *   The configuration key to check if it has changed.
+   *
+   * @return bool
+   */
+  public function isChanged($key) {
+    return $this->config->get($key) !== $this->config->getOriginal($key);
+  }
+
+}
+
diff --git a/core/lib/Drupal/Core/Config/ConfigEvent.php b/core/lib/Drupal/Core/Config/ConfigEvent.php
deleted file mode 100644
index 5b07098..0000000
--- a/core/lib/Drupal/Core/Config/ConfigEvent.php
+++ /dev/null
@@ -1,33 +0,0 @@
-<?php
-
-namespace Drupal\Core\Config;
-
-use Symfony\Component\EventDispatcher\Event;
-
-class ConfigEvent extends Event {
-
-  /**
-   * Configuration object.
-   *
-   * @var \Drupal\Core\Config\Config
-   */
-  protected $config;
-
-  /**
-   * Constructs a configuration event object.
-   *
-   * @param \Drupal\Core\Config\Config
-   *   Configuration object.
-   */
-  public function __construct(Config $config) {
-    $this->config = $config;
-  }
-
-  /**
-   * Get configuration object.
-   */
-  public function getConfig() {
-    return $this->config;
-  }
-}
-
diff --git a/core/lib/Drupal/Core/Config/ConfigEvents.php b/core/lib/Drupal/Core/Config/ConfigEvents.php
new file mode 100644
index 0000000..3049932
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/ConfigEvents.php
@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Config\Config\ConfigEvents.
+ */
+
+namespace Drupal\Core\Config;
+
+/**
+ * Defines events for the configuration system.
+ */
+class ConfigEvents {
+
+  /**
+   * Name of event fired when saving the configuration object.
+   *
+   * @see \Drupal\Core\Config\Config::save()
+   * @see \Drupal\Core\Config\ConfigFactory::onConfigSave()
+   */
+  const SAVE = 'config.save';
+
+  /**
+   * Name of event fired when deleting the configuration object.
+   *
+   * @see \Drupal\Core\Config\Config::delete()
+   */
+  const DELETE = 'config.delete';
+
+  /**
+   * Name of event fired when collecting overrides for configuration objects.
+   *
+   * @see \Drupal\Core\Config\ConfigFactory::loadModuleOverrides().
+   */
+  const MODULE_OVERRIDES = 'config.module.overrides';
+
+  /**
+   * Name of event fired when renaming a configuration object.
+   *
+   * @see \Drupal\Core\Config\ConfigFactory::rename().
+   */
+  const RENAME = 'config.rename';
+
+  /**
+   * Name of event fired when validating in the configuration import process.
+   *
+   * @see \Drupal\Core\Config\ConfigImporter::validate().
+   * @see \Drupal\Core\EventSubscriber\ConfigImportSubscriber::onConfigImporterValidate().
+   */
+  const VALIDATE = 'config.importer.validate';
+
+  /**
+   * Name of event fired when when importing configuration to target storage.
+   *
+   * @see \Drupal\Core\Config\ConfigImporter::import().
+   * @see \Drupal\Core\EventSubscriber\ConfigSnapshotSubscriber::onConfigImporterImport().
+   */
+  const IMPORT = 'config.importer.import';
+}
diff --git a/core/lib/Drupal/Core/Config/ConfigFactory.php b/core/lib/Drupal/Core/Config/ConfigFactory.php
index 7029d11..6f946ef 100644
--- a/core/lib/Drupal/Core/Config/ConfigFactory.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactory.php
@@ -223,7 +223,7 @@ public function loadMultiple(array $names) {
    */
   protected function loadModuleOverrides(array $names) {
     $configOverridesEvent = new ConfigModuleOverridesEvent($names, $this->language);
-    $this->eventDispatcher->dispatch('config.module.overrides', $configOverridesEvent);
+    $this->eventDispatcher->dispatch(ConfigEvents::MODULE_OVERRIDES, $configOverridesEvent);
     return $configOverridesEvent->getOverrides();
   }
 
@@ -258,12 +258,10 @@ public function rename($old_name, $new_name) {
       unset($this->cache[$old_cache_key]);
     }
 
-    $new_cache_key = $this->getCacheKey($new_name);
-    $this->cache[$new_cache_key] = new Config($new_name, $this->storage, $this->eventDispatcher, $this->typedConfigManager, $this->language);
-    if ($data = $this->storage->read($new_name)) {
-      $this->cache[$new_cache_key]->initWithData($data);
-    }
-    return $this->cache[$new_cache_key];
+    // Prime the cache and load the configuration with the correct overrides.
+    $config = $this->get($new_name);
+    $this->eventDispatcher->dispatch(ConfigEvents::RENAME, new ConfigRenameEvent($config, $old_name));
+    return $config;
   }
 
   /**
@@ -363,10 +361,10 @@ protected function canOverride($name) {
   /**
    * Removes stale static cache entries when configuration is saved.
    *
-   * @param ConfigEvent $event
+   * @param ConfigCrudEvent $event
    *   The configuration event.
    */
-  public function onConfigSave(ConfigEvent $event) {
+  public function onConfigSave(ConfigCrudEvent $event) {
     // Ensure that the static cache contains up to date configuration objects by
     // replacing the data on any entries for the configuration object apart
     // from the one that references the actual config object being saved.
@@ -383,7 +381,7 @@ public function onConfigSave(ConfigEvent $event) {
    * {@inheritdoc}
    */
   static function getSubscribedEvents() {
-    $events['config.save'][] = array('onConfigSave', 255);
+    $events[ConfigEvents::SAVE][] = array('onConfigSave', 255);
     return $events;
   }
 
diff --git a/core/lib/Drupal/Core/Config/ConfigImporter.php b/core/lib/Drupal/Core/Config/ConfigImporter.php
index e2354f4..d14a45e 100644
--- a/core/lib/Drupal/Core/Config/ConfigImporter.php
+++ b/core/lib/Drupal/Core/Config/ConfigImporter.php
@@ -23,11 +23,11 @@
  *
  * The ConfigImporter has a identifier which is used to construct event names.
  * The events fired during an import are:
- * - 'config.importer.validate': Events listening can throw a
+ * - ConfigEvents::VALIDATE: Events listening can throw a
  *   \Drupal\Core\Config\ConfigImporterException to prevent an import from
  *   occurring.
  *   @see \Drupal\Core\EventSubscriber\ConfigImportSubscriber
- * - 'config.importer.import': Events listening can react to a successful import.
+ * - ConfigEvents::IMPORT: Events listening can react to a successful import.
  *   @see \Drupal\Core\EventSubscriber\ConfigSnapshotSubscriber
  *
  * @see \Drupal\Core\Config\ConfigImporterEvent
diff --git a/core/lib/Drupal/Core/Config/ConfigRenameEvent.php b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php
new file mode 100644
index 0000000..83a3874
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/ConfigRenameEvent.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Config\ConfigRenameEvent.
+ */
+
+namespace Drupal\Core\Config;
+
+/**
+ * Configuration event fired when renaming a configuration object.
+ */
+class ConfigRenameEvent extends ConfigCrudEvent {
+
+  /**
+   * The old configuration object name.
+   *
+   * @var string
+   */
+  protected $oldName;
+
+  /**
+   * Constructs the config rename event.
+   *
+   * @param \Drupal\Core\Config\Config $config
+   *   The configuration that has been renamed.
+   * @param string $old_name
+   *   The old configuration object name.
+   */
+  public function __construct(Config $config, $old_name) {
+    $this->config = $config;
+    $this->oldName = $old_name;
+  }
+
+  /**
+   * Gets the old configuration object name.
+   *
+   * @return string
+   *   The old configuration object name.
+   */
+  public function getOldName() {
+    return $this->oldName;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
index 6cd3129..16267f4 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\EventSubscriber;
 
 use Drupal\Core\Config\Config;
+use Drupal\Core\Config\ConfigEvents;
 use Drupal\Core\Config\ConfigImporterEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
@@ -40,7 +41,7 @@ public function onConfigImporterValidate(ConfigImporterEvent $event) {
    *   An array of event listener definitions.
    */
   static function getSubscribedEvents() {
-    $events['config.importer.validate'][] = array('onConfigImporterValidate', 40);
+    $events[ConfigEvents::VALIDATE][] = array('onConfigImporterValidate', 40);
     return $events;
   }
 
diff --git a/core/lib/Drupal/Core/EventSubscriber/ConfigSnapshotSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ConfigSnapshotSubscriber.php
index 54c60dc..e920e0f 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ConfigSnapshotSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ConfigSnapshotSubscriber.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core\EventSubscriber;
 
-use Drupal\Core\Config\Config;
+use Drupal\Core\Config\ConfigEvents;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Config\ConfigImporterEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
@@ -61,7 +61,7 @@ public function onConfigImporterImport(ConfigImporterEvent $event) {
    *   An array of event listener definitions.
    */
   static function getSubscribedEvents() {
-    $events['config.importer.import'][] = array('onConfigImporterImport', 40);
+    $events[ConfigEvents::IMPORT][] = array('onConfigImporterImport', 40);
     return $events;
   }
 
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigEventsTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigEventsTest.php
new file mode 100644
index 0000000..27e8845
--- /dev/null
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigEventsTest.php
@@ -0,0 +1,90 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\config\Tests\ConfigEventsTest.
+ */
+
+namespace Drupal\config\Tests;
+
+use Drupal\Core\Config\Config;
+use Drupal\Core\Config\ConfigEvents;
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests CRUD operations on configuration objects.
+ */
+class ConfigEventsTest extends DrupalUnitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('config_events_test');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Config events',
+      'description' => 'Tests events fired on configuration objects.',
+      'group' => 'Configuration',
+    );
+  }
+
+  /**
+   * Tests configuration events.
+   */
+  function testConfigEvents() {
+    $name = 'config_events_test.test';
+
+    $config = new Config($name, \Drupal::service('config.storage'), \Drupal::service('event_dispatcher'), \Drupal::service('config.typed'));
+    $config->set('key', 'initial');
+    \Drupal::state()->get('config_events_test.event', FALSE);
+    $this->assertIdentical(\Drupal::state()->get('config_events_test.event', array()), array(), 'No events fired by creating a new configuration object');
+    $config->save();
+
+    $event = \Drupal::state()->get('config_events_test.event', array());
+    $this->assertIdentical($event['event_name'], ConfigEvents::SAVE);
+    $this->assertIdentical($event['current_config_data'], array('key' => 'initial'));
+    $this->assertIdentical($event['raw_config_data'], array('key' => 'initial'));
+    $this->assertIdentical($event['original_config_data'], array());
+
+    $config->set('key', 'updated')->save();
+    $event = \Drupal::state()->get('config_events_test.event', array());
+    $this->assertIdentical($event['event_name'], ConfigEvents::SAVE);
+    $this->assertIdentical($event['current_config_data'], array('key' => 'updated'));
+    $this->assertIdentical($event['raw_config_data'], array('key' => 'updated'));
+    $this->assertIdentical($event['original_config_data'], array('key' => 'initial'));
+
+    $config->delete();
+    $event = \Drupal::state()->get('config_events_test.event', array());
+    $this->assertIdentical($event['event_name'], ConfigEvents::DELETE);
+    $this->assertIdentical($event['current_config_data'], array());
+    $this->assertIdentical($event['raw_config_data'], array());
+    $this->assertIdentical($event['original_config_data'], array('key' => 'updated'));
+  }
+
+  /**
+   * Tests configuration rename event that is fired from the ConfigFactory.
+   */
+  function testConfigRenameEvent() {
+    $name = 'config_events_test.test';
+    $new_name = 'config_events_test.test_rename';
+    $GLOBALS['config'][$name] = array('key' => 'overridden');
+    $GLOBALS['config'][$new_name] = array('key' => 'new overridden');
+
+    $config = \Drupal::config($name);
+    $config->set('key', 'initial')->save();
+    $event = \Drupal::state()->get('config_events_test.event', array());
+    $this->assertIdentical($event['event_name'], ConfigEvents::SAVE);
+    $this->assertIdentical($event['current_config_data'], array('key' => 'overridden'));
+
+    \Drupal::configFactory()->rename($name, $new_name);
+    $event = \Drupal::state()->get('config_events_test.event', array());
+    $this->assertIdentical($event['event_name'], ConfigEvents::RENAME);
+    $this->assertIdentical($event['current_config_data'], array('key' => 'new overridden'));
+    $this->assertIdentical($event['raw_config_data'], array('key' => 'initial'));
+    $this->assertIdentical($event['original_config_data'], array('key' => 'new overridden'));
+  }
+
+}
diff --git a/core/modules/config/tests/config_events_test/config_events_test.info.yml b/core/modules/config/tests/config_events_test/config_events_test.info.yml
new file mode 100644
index 0000000..6cb7504
--- /dev/null
+++ b/core/modules/config/tests/config_events_test/config_events_test.info.yml
@@ -0,0 +1,6 @@
+name: 'Configuration events test'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_events_test/config_events_test.module b/core/modules/config/tests/config_events_test/config_events_test.module
new file mode 100644
index 0000000..aa52475
--- /dev/null
+++ b/core/modules/config/tests/config_events_test/config_events_test.module
@@ -0,0 +1,6 @@
+<?php
+
+/**
+ * @file
+ * Provides Config event listeners for testing purposes.
+ */
diff --git a/core/modules/config/tests/config_events_test/config_events_test.services.yml b/core/modules/config/tests/config_events_test/config_events_test.services.yml
new file mode 100644
index 0000000..12d6fb1
--- /dev/null
+++ b/core/modules/config/tests/config_events_test/config_events_test.services.yml
@@ -0,0 +1,6 @@
+services:
+  config_events_test.event_subscriber:
+    class: Drupal\config_events_test\EventSubscriber
+    arguments: ['@state']
+    tags:
+      - { name: event_subscriber }
diff --git a/core/modules/config/tests/config_events_test/lib/Drupal/config_events_test/EventSubscriber.php b/core/modules/config/tests/config_events_test/lib/Drupal/config_events_test/EventSubscriber.php
new file mode 100644
index 0000000..853332d
--- /dev/null
+++ b/core/modules/config/tests/config_events_test/lib/Drupal/config_events_test/EventSubscriber.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\config_events_test\EventSubscriber.
+ */
+
+namespace Drupal\config_events_test;
+
+
+use Drupal\Core\Config\ConfigCrudEvent;
+use Drupal\Core\Config\ConfigEvents;
+use Drupal\Core\KeyValueStore\StateInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+class EventSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The state key value store.
+   *
+   * @var \Drupal\Core\KeyValueStore\StateInterface
+   */
+  protected $state;
+
+  /**
+   * Constructs the Event Subscriber object.
+   *
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
+   *   The state key value store.
+   */
+  public function __construct(StateInterface $state) {
+    $this->state = $state;
+  }
+
+  /**
+   * Reacts to config event.
+   *
+   * @param \Drupal\Core\Config\ConfigCrudEvent $event
+   *   The configuration event.
+   */
+  public function configEventRecorder(ConfigCrudEvent $event) {
+    $config = $event->getConfig();
+    $this->state->set('config_events_test.event', array(
+      'event_name' => $event->getName(),
+      'current_config_data' => $config->get(),
+      'original_config_data' => $config->getOriginal(),
+      'raw_config_data' => $config->getRawData()
+    ));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  static function getSubscribedEvents() {
+    $events[ConfigEvents::SAVE][] = array('configEventRecorder');
+    $events[ConfigEvents::DELETE][] = array('configEventRecorder');
+    $events[ConfigEvents::RENAME][] = array('configEventRecorder');
+    return $events;
+  }
+}
diff --git a/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleLowPriorityOverrideSubscriber.php b/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleLowPriorityOverrideSubscriber.php
index 1e1b5ef..fd7e26c 100644
--- a/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleLowPriorityOverrideSubscriber.php
+++ b/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleLowPriorityOverrideSubscriber.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\config_override\EventSubscriber;
 
+use Drupal\Core\Config\ConfigEvents;
 use Drupal\Core\Config\ConfigModuleOverridesEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
@@ -36,7 +37,7 @@ public function onConfigModuleOverride(ConfigModuleOverridesEvent $event) {
    *   An array of event listener definitions.
    */
   static function getSubscribedEvents() {
-    $events['config.module.overrides'][] = array('onConfigModuleOverride', 35);
+    $events[ConfigEvents::MODULE_OVERRIDES][] = array('onConfigModuleOverride', 35);
     return $events;
   }
 }
diff --git a/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleOverrideSubscriber.php b/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleOverrideSubscriber.php
index 54f0f64..e168111 100644
--- a/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleOverrideSubscriber.php
+++ b/core/modules/config/tests/config_override/lib/Drupal/config_override/EventSubscriber/ConfigModuleOverrideSubscriber.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\config_override\EventSubscriber;
 
+use Drupal\Core\Config\ConfigEvents;
 use Drupal\Core\Config\ConfigModuleOverridesEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
@@ -34,7 +35,7 @@ public function onConfigModuleOverride(ConfigModuleOverridesEvent $event) {
    *   An array of event listener definitions.
    */
   static function getSubscribedEvents() {
-    $events['config.module.overrides'][] = array('onConfigModuleOverride', 40);
+    $events[ConfigEvents::MODULE_OVERRIDES][] = array('onConfigModuleOverride', 40);
     return $events;
   }
 }
diff --git a/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
index 819c2d3..82b6f9d 100644
--- a/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
+++ b/core/modules/language/lib/Drupal/language/EventSubscriber/ConfigSubscriber.php
@@ -8,7 +8,8 @@
 namespace Drupal\language\EventSubscriber;
 
 use Drupal\Component\PhpStorage\PhpStorageFactory;
-use Drupal\Core\Config\ConfigEvent;
+use Drupal\Core\Config\ConfigCrudEvent;
+use Drupal\Core\Config\ConfigEvents;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 /**
@@ -19,12 +20,12 @@ class ConfigSubscriber implements EventSubscriberInterface {
   /**
    * Causes the container to be rebuilt on the next request.
    *
-   * @param ConfigEvent $event
+   * @param ConfigCrudEvent $event
    *   The configuration event.
    */
-  public function onConfigSave(ConfigEvent $event) {
+  public function onConfigSave(ConfigCrudEvent $event) {
     $saved_config = $event->getConfig();
-    if ($saved_config->getName() == 'system.site' && $saved_config->get('langcode') != $saved_config->getOriginal('langcode')) {
+    if ($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 @@ public function onConfigSave(ConfigEvent $event) {
    * {@inheritdoc}
    */
   static function getSubscribedEvents() {
-    $events['config.save'][] = array('onConfigSave', 0);
+    $events[ConfigEvents::SAVE][] = array('onConfigSave', 0);
     return $events;
   }
 
diff --git a/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php b/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
index d6e1fc6..4abc714 100644
--- a/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
+++ b/core/modules/system/lib/Drupal/system/SystemConfigSubscriber.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\system;
 
+use Drupal\Core\Config\ConfigEvents;
 use Drupal\Core\Config\ConfigImporterEvent;
 use Drupal\Core\Config\ConfigImporterException;
 use Drupal\Core\Config\StorageDispatcher;
@@ -21,7 +22,7 @@ class SystemConfigSubscriber implements EventSubscriberInterface {
    * {@inheritdoc}
    */
   static function getSubscribedEvents() {
-    $events['config.importer.validate'][] = array('onConfigImporterValidate', 20);
+    $events[ConfigEvents::VALIDATE][] = array('onConfigImporterValidate', 20);
     return $events;
   }