diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index 0b59cfe..af42875 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -3417,7 +3417,7 @@ function _menu_router_save($menu, $masks) {
  */
 function _menu_site_is_offline($check_only = FALSE) {
   // Check if site is in maintenance mode.
-  if (Drupal::config('system.maintenance')->get('enabled')) {
+  if (Drupal::state()->get('system.maintenance_mode')) {
     if (user_access('access site in maintenance mode')) {
       // Ensure that the maintenance mode message is displayed only once
       // (allowing for page redirects) and specifically suppress its display on
diff --git a/core/includes/update.inc b/core/includes/update.inc
index 4bd4e16..0808cfc 100644
--- a/core/includes/update.inc
+++ b/core/includes/update.inc
@@ -880,11 +880,8 @@ function update_batch($start, $redirect = NULL, $url = NULL, $batch = array(), $
     $_SESSION['maintenance_mode'] = $maintenance_mode;
   }
   if (empty($_SESSION['maintenance_mode'])) {
-    $GLOBALS['conf']['system.maintenance']['enabled'] = TRUE;
-    // @todo This is borderline state, not config. Or a global system
-    //   "maintenance lock".
-    if (db_table_exists('config')) {
-      Drupal::config('system.maintenance')->set('enabled', TRUE)->save();
+    if (db_table_exists('state')) {
+      Drupal::state()->set('system.maintenance_mode', TRUE);
     }
   }
 
@@ -956,9 +953,7 @@ function update_finished($success, $results, $operations) {
   // Now that the update is done, we can put the site back online if it was
   // previously in maintenance mode.
   if (isset($_SESSION['maintenance_mode'])) {
-    $GLOBALS['conf']['system.maintenance']['enabled'] = FALSE;
-    // At this point, the configuration system should exist.
-    Drupal::config('system.maintenance')->set('enabled', FALSE)->save();
+    Drupal::state()->set('system.maintenance_mode', FALSE);
     unset($_SESSION['maintenance_mode']);
   }
 }
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
index e1ea9b7..2a36208 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTest.php
@@ -83,10 +83,6 @@ function testSchemaMapping() {
     $expected = array();
     $expected['label'] = 'Maintenance mode';
     $expected['class'] = '\Drupal\Core\Config\Schema\Mapping';
-    $expected['mapping']['enabled'] = array(
-      'label' => 'Put site into maintenance mode',
-      'type' => 'boolean'
-    );
     $expected['mapping']['message'] = array(
       'label' =>  'Message to display when in maintenance mode',
       'type' => 'text',
diff --git a/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
index 46143fd..6572ee8 100644
--- a/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -40,9 +40,6 @@ system.maintenance:
   type: mapping
   label: 'Maintenance mode'
   mapping:
-    enabled:
-      type: boolean
-      label: 'Put site into maintenance mode'
     message:
       type: text
       label: 'Message to display when in maintenance mode'
diff --git a/core/modules/system/lib/Drupal/system/Access/CronAccessCheck.php b/core/modules/system/lib/Drupal/system/Access/CronAccessCheck.php
index 05a131d..ccff863 100644
--- a/core/modules/system/lib/Drupal/system/Access/CronAccessCheck.php
+++ b/core/modules/system/lib/Drupal/system/Access/CronAccessCheck.php
@@ -32,7 +32,7 @@ public function access(Route $route, Request $request) {
       watchdog('cron', 'Cron could not run because an invalid key was used.', array(), WATCHDOG_NOTICE);
       return static::KILL;
     }
-    elseif (\Drupal::config('system.maintenance')->get('enabled')) {
+    elseif (\Drupal::state()->get('system.maintenance_mode')) {
       watchdog('cron', 'Cron could not run because the site is in maintenance mode.', array(), WATCHDOG_NOTICE);
       return static::KILL;
     }
diff --git a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
index a196cda..e83b93f 100644
--- a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
@@ -7,7 +7,12 @@
 
 namespace Drupal\system\Form;
 
+use Drupal\Core\Config\ConfigFactory;
+use Drupal\Core\Config\Context\ContextInterface;
+use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
 use Drupal\system\SystemConfigFormBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
 
 /**
  * Configure maintenance settings for this site.
@@ -15,6 +20,38 @@
 class SiteMaintenanceModeForm extends SystemConfigFormBase {
 
   /**
+   * The state keyvalue collection.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   */
+  protected $state;
+
+  /**
+   * Constructs a \Drupal\system\SystemConfigFormBase object.
+   *
+   * @param \Drupal\Core\Config\ConfigFactory $config_factory
+   *   The factory for configuration objects.
+   * @param \Drupal\Core\Config\Context\ContextInterface $context
+   *   The configuration context to use.
+   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   *   The state keyvalue collection to use.
+   */
+  public function __construct(ConfigFactory $config_factory, ContextInterface $context, KeyValueStoreInterface $state) {
+    parent::__construct($config_factory, $context);
+    $this->state = $state;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('config.factory'),
+      $container->get('config.context.free'),
+      $container->get('state')
+    );
+  }
+  /**
    * {@inheritdoc}
    */
   public function getFormID() {
@@ -29,7 +66,7 @@ public function buildForm(array $form, array &$form_state) {
     $form['maintenance_mode'] = array(
       '#type' => 'checkbox',
       '#title' => t('Put site into maintenance mode'),
-      '#default_value' => $config->get('enabled'),
+      '#default_value' => $this->state->get('system.maintenance_mode'),
       '#description' => t('Visitors will only see the maintenance mode message. Only users with the "Access site in maintenance mode" <a href="@permissions-url">permission</a> will be able to access the site. Authorized users can log in directly via the <a href="@user-login">user login</a> page.', array('@permissions-url' => url('admin/config/people/permissions'), '@user-login' => url('user'))),
     );
     $form['maintenance_mode_message'] = array(
@@ -46,10 +83,10 @@ public function buildForm(array $form, array &$form_state) {
    */
   public function submitForm(array &$form, array &$form_state) {
     $this->configFactory->get('system.maintenance')
-      ->set('enabled', $form_state['values']['maintenance_mode'])
       ->set('message', $form_state['values']['maintenance_mode_message'])
       ->save();
 
+    $this->state->set('system.maintenance_mode', $form_state['values']['maintenance_mode']);
     parent::submitForm($form, $form_state);
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
index 31ef055..38cbba9 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/MenuRouterTest.php
@@ -151,7 +151,7 @@ function testExoticPath() {
    * Test the theme callback when the site is in maintenance mode.
    */
   function testThemeCallbackMaintenanceMode() {
-    \Drupal::config('system.maintenance')->set('enabled', 1)->save();
+    $this->container->get('state')->set('system.maintenance_mode', TRUE);
     theme_enable(array($this->admin_theme));
 
     // For a regular user, the fact that the site is in maintenance mode means
@@ -166,7 +166,7 @@ function testThemeCallbackMaintenanceMode() {
     $this->assertText('Custom theme: seven. Actual theme: seven.', 'The theme callback system is correctly triggered for an administrator when the site is in maintenance mode.');
     $this->assertRaw('seven/style.css', "The administrative theme's CSS appears on the page.");
 
-    \Drupal::config('system.maintenance')->set('enabled', 0)->save();
+    $this->container->get('state')->set('system.maintenance_mode', FALSE);
   }
 
   /**
@@ -175,7 +175,7 @@ function testThemeCallbackMaintenanceMode() {
    * @see \Drupal\menu_test\EventSubscriber\MaintenanceModeSubscriber::onKernelRequestMaintenance().
    */
   function testMaintenanceModeLoginPaths() {
-    \Drupal::config('system.maintenance')->set('enabled', 1)->save();
+    $this->container->get('state')->set('system.maintenance_mode', TRUE);
 
     $offline_message = t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => \Drupal::config('system.site')->get('name')));
     $this->drupalGet('test-page');
@@ -183,7 +183,7 @@ function testMaintenanceModeLoginPaths() {
     $this->drupalGet('menu_login_callback');
     $this->assertText('This is TestControllers::testLogin.', 'Maintenance mode can be bypassed using an event subscriber.');
 
-    \Drupal::config('system.maintenance')->set('enabled', 0)->save();
+    $this->container->get('state')->set('system.maintenance_mode', FALSE);
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/SystemUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/SystemUpgradePathTest.php
index 4b22f93..6b0ad23 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/SystemUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/SystemUpgradePathTest.php
@@ -45,7 +45,6 @@ public function testVariableUpgrade() {
     );
 
     $expected_config['system.maintenance'] = array(
-      'enabled' => '1',
       'message' => 'Testing config upgrade',
     );
 
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 447320c..5222f25 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1480,9 +1480,11 @@ function system_update_8015() {
  */
 function system_update_8016() {
   update_variables_to_config('system.maintenance', array(
-    'maintenance_mode' => 'enabled',
     'maintenance_mode_message' => 'message',
   ));
+  update_variables_to_state(array(
+    'maintenance_mode' => 'system.maintenance_mode',
+  ));
 }
 
 /**
diff --git a/core/modules/update/update.authorize.inc b/core/modules/update/update.authorize.inc
index ee1e6fb..ab5f5bc 100644
--- a/core/modules/update/update.authorize.inc
+++ b/core/modules/update/update.authorize.inc
@@ -191,7 +191,7 @@ function update_authorize_update_batch_finished($success, $results) {
       $success = FALSE;
     }
   }
-  $offline = Drupal::config('system.maintenance')->get('enabled');
+  $offline = Drupal::state()->get('system.maintenance_mode');
   if ($success) {
     // Now that the update completed, we need to clear the available update data
     // and recompute our status, so prevent show bogus results.
@@ -199,7 +199,7 @@ function update_authorize_update_batch_finished($success, $results) {
 
     // Take the site out of maintenance mode if it was previously that way.
     if ($offline && isset($_SESSION['maintenance_mode']) && $_SESSION['maintenance_mode'] == FALSE) {
-      Drupal::config('system.maintenance')->set('enabled', FALSE)->save();
+      Drupal::state()->set('system.maintenance_mode', FALSE);
       $page_message = array(
         'message' => t('Update was completed successfully. Your site has been taken out of maintenance mode.'),
         'type' => 'status',
@@ -258,11 +258,11 @@ function update_authorize_install_batch_finished($success, $results) {
       $success = FALSE;
     }
   }
-  $offline = Drupal::config('system.maintenance')->get('enabled');
+  $offline = Drupal::state()->get('system.maintenance_mode');
   if ($success) {
     // Take the site out of maintenance mode if it was previously that way.
     if ($offline && isset($_SESSION['maintenance_mode']) && $_SESSION['maintenance_mode'] == FALSE) {
-      Drupal::config('system.maintenance')->set('enabled', FALSE)->save();
+      Drupal::state()->set('system.maintenance_mode', FALSE);
       $page_message = array(
         'message' => t('Installation was completed successfully. Your site has been taken out of maintenance mode.'),
         'type' => 'status',
diff --git a/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
index 9e9d73a..d2c66ee 100644
--- a/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -430,9 +430,9 @@ function update_manager_update_ready_form($form, &$form_state) {
  */
 function update_manager_update_ready_form_submit($form, &$form_state) {
   // Store maintenance_mode setting so we can restore it when done.
-  $_SESSION['maintenance_mode'] = Drupal::config('system.maintenance')->get('enabled');
+  $_SESSION['maintenance_mode'] = Drupal::state()->get('system.maintenance_mode');
   if ($form_state['values']['maintenance_mode'] == TRUE) {
-    Drupal::config('system.maintenance')->set('enabled', TRUE)->save();
+    Drupal::state()->set('system.maintenance_mode', TRUE);
   }
 
   if (!empty($_SESSION['update_manager_update_projects'])) {