diff --git a/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php b/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php
deleted file mode 100644
index 32ad9b7..0000000
--- a/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php
+++ /dev/null
@@ -1,64 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\DependencyInjection\UpdateServiceProvider.
- */
-
-namespace Drupal\Core\DependencyInjection;
-
-use Symfony\Component\DependencyInjection\Reference;
-use Symfony\Component\HttpFoundation\Request;
-
-/**
- * ServiceProvider class for update.php service overrides.
- *
- * This class is manually added by update.php via $conf['container_service_providers']
- * and required to prevent various services from trying to retrieve data from
- * storages that do not exist yet.
- */
-class UpdateServiceProvider implements ServiceProviderInterface, ServiceModifierInterface {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function register(ContainerBuilder $container) {
-    if (!empty($GLOBALS['conf']['update_service_provider_overrides'])) {
-      // Disable the Lock service.
-      $container
-        ->register('lock', 'Drupal\Core\Lock\NullLockBackend');
-
-      // Prevent config from being accessed via a cache wrapper by removing
-      // any existing definition and setting an alias to the actual storage.
-      $container->removeDefinition('config.storage');
-      $container->setAlias('config.storage', 'config.storage.active');
-
-      $container
-        ->register('cache_factory', 'Drupal\Core\Cache\MemoryBackendFactory');
-      $container
-        ->register('router.builder', 'Drupal\Core\Routing\RouteBuilderStatic');
-
-      $container->register('theme_handler', 'Drupal\Core\Extension\ThemeHandler')
-        ->addArgument(new Reference('config.factory'))
-        ->addArgument(new Reference('module_handler'))
-        ->addArgument(new Reference('state'))
-        ->addArgument(new Reference('info_parser'));
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function alter(ContainerBuilder $container) {
-    // Ensure that URLs generated for the home and admin pages don't have
-    // 'update.php' in them.
-    $request = Request::createFromGlobals();
-    $definition = $container->getDefinition('url_generator');
-    $definition->addMethodCall('setBasePath', array(str_replace('/core', '', $request->getBasePath()) . '/'));
-    // We need to set the script path to an empty string since the value
-    // determined by \Drupal\Core\Routing\UrlGenerator::setRequest() is invalid
-    // once '/core' has been removed from the base path.
-    $definition->addMethodCall('setScriptPath', array(''));
-  }
-
-}
diff --git a/core/modules/system/src/Controller/DbUpdateController.php b/core/modules/system/src/Controller/DbUpdateController.php
index 0e11e1e..2526a18 100644
--- a/core/modules/system/src/Controller/DbUpdateController.php
+++ b/core/modules/system/src/Controller/DbUpdateController.php
@@ -107,24 +107,23 @@ public static function create(ContainerInterface $container) {
   public function handle($op, Request $request) {
     require_once DRUPAL_ROOT . '/core/includes/install.inc';
     require_once DRUPAL_ROOT . '/core/includes/update.inc';
-    require_once DRUPAL_ROOT . '/core/modules/system/system.install';
+
+    drupal_load_updates();
+    update_fix_compatibility();
+
+    if ($request->query->get('continue')) {
+      $_SESSION['update_ignore_warnings'] = TRUE;
+    }
 
     $regions = array();
     $requirements = update_check_requirements();
     $severity = drupal_requirements_severity($requirements);
-    if ($severity == REQUIREMENT_ERROR || $severity == REQUIREMENT_WARNING) {
+    if ($severity == REQUIREMENT_ERROR || ($severity == REQUIREMENT_WARNING && empty($_SESSION['update_ignore_warnings']))) {
       $regions['sidebar_first'] = $this->updateTasksList('requirements');
-      $output = $this->requirementsPage($severity, $requirements);
+      $output = $this->requirements($severity, $requirements);
     }
     else {
-      require_once DRUPAL_ROOT . '/core/includes/batch.inc';
-      drupal_load_updates();
-
-      update_fix_compatibility();
-
       switch ($op) {
-        // update.php ops.
-
         case 'selection':
           $regions['sidebar_first'] = $this->updateTasksList('selection');
           $output = $this->selection();
@@ -147,6 +146,7 @@ public function handle($op, Request $request) {
 
         // Regular batch ops : defer to batch processing API.
         default:
+          require_once DRUPAL_ROOT . '/core/includes/batch.inc';
           $regions['sidebar_first'] = $this->updateTasksList('run');
           $output = _batch_page($request);
           break;
@@ -425,6 +425,7 @@ protected function results() {
     }
     unset($_SESSION['update_results']);
     unset($_SESSION['update_success']);
+    unset($_SESSION['update_ignore_warnings']);
 
     return $build;
   }
@@ -435,11 +436,14 @@ protected function results() {
    * @return array
    *   A render array.
    */
-  public function requirementsPage(array $requirements) {
+  public function requirements($severity, array $requirements) {
+    $options = $severity == REQUIREMENT_WARNING ? array('continue' => 1) : array();
+    $try_again_url = $this->url('system.db_update', $options);
+
     $build['status_report'] = array(
       '#theme' => 'status_report',
       '#requirements' => $requirements,
-      '#suffix' => $this->t('Check the messages and <a href="@url">try again</a>.', array('@url' => $this->url('system.db_update')))
+      '#suffix' => $this->t('Check the messages and <a href="@url">try again</a>.', array('@url' => $try_again_url))
     );
 
     $build['#title'] = $this->t('Requirements problem');
@@ -488,9 +492,7 @@ protected function triggerBatch(Request $request) {
       $_SESSION['maintenance_mode'] = $maintenance_mode;
     }
     if (empty($_SESSION['maintenance_mode'])) {
-      if (db_table_exists('state')) {
-        $this->state->set('system.maintenance_mode', TRUE);
-      }
+      $this->state->set('system.maintenance_mode', TRUE);
     }
 
     $start = $this->getModuleUpdates();
@@ -550,10 +552,6 @@ protected function triggerBatch(Request $request) {
    *   A list of all the operations that had not been completed by the batch API.
    */
   public static function batchFinished($success, $results, $operations) {
-    // Clear the caches in case the data has been updated.
-    $GLOBALS['conf']['update_service_provider_overrides'] = FALSE;
-    \Drupal::service('kernel')->updateModules(\Drupal::moduleHandler()->getModuleList());
-
     // No updates to run, so caches won't get flushed later.  Clear them now.
     drupal_flush_all_caches();
 
@@ -580,7 +578,7 @@ protected function helpfulLinks() {
       'title' => $this->t('Front page'),
       'href' => '<front>',
     );
-    if (user_access('access administration pages')) {
+    if ($this->account->hasPermission('access administration pages')) {
       $links['admin-pages'] = array(
         'title' => $this->t('Administration pages'),
         'href' => 'admin',
diff --git a/core/modules/system/src/Tests/Update/InvalidUpdateHook.php b/core/modules/system/src/Tests/Update/InvalidUpdateHook.php
index 460d03f..1587c43 100644
--- a/core/modules/system/src/Tests/Update/InvalidUpdateHook.php
+++ b/core/modules/system/src/Tests/Update/InvalidUpdateHook.php
@@ -48,7 +48,7 @@ function setUp() {
     parent::setUp();
     require_once DRUPAL_ROOT . '/core/includes/update.inc';
 
-    $this->update_url = $GLOBALS['base_url'] . '/core/update.php';
+    $this->update_url = $GLOBALS['base_url'] . '/update.php';
     $this->update_user = $this->drupalCreateUser(array('administer software updates'));
   }
 
@@ -56,7 +56,7 @@ function testInvalidUpdateHook() {
     // Confirm that a module with hook_update_8000() cannot be updated.
     $this->drupalLogin($this->update_user);
     $this->drupalGet($this->update_url);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('Some of the pending updates cannot be applied because their dependencies were not met.'));
   }
 
diff --git a/core/modules/system/src/Tests/Update/UpdateScriptTest.php b/core/modules/system/src/Tests/Update/UpdateScriptTest.php
index cd92191..c709cdd 100644
--- a/core/modules/system/src/Tests/Update/UpdateScriptTest.php
+++ b/core/modules/system/src/Tests/Update/UpdateScriptTest.php
@@ -36,30 +36,8 @@ public static function getInfo() {
 
   function setUp() {
     parent::setUp();
-    $this->update_url = $GLOBALS['base_url'] . '/core/update.php';
-    $this->update_user = $this->drupalCreateUser(array('administer software updates'));
-  }
-
-  /**
-   * Tests that updates from schema versions prior to 8000 are prevented.
-   */
-  function testInvalidMigration() {
-    // Mock a D7 system table so that the schema value of the system module
-    // can be retrieved.
-    db_create_table('system', $this->getSystemSchema());
-    // Assert that the table exists.
-    $this->assertTrue(db_table_exists('system'), 'The table exists.');
-    // Insert a value for the system module.
-    db_insert('system')
-      ->fields(array(
-        'name' => 'system',
-        'schema_version' => 7000,
-      ))
-      ->execute();
-    $system_schema = db_query('SELECT schema_version FROM {system} WHERE name = :system', array(':system' => 'system'))->fetchField();
-    $this->drupalGet($this->update_url, array('external' => TRUE));
-    $text = 'Your system schema version is ' . $system_schema . '. Updating directly from a schema version prior to 8000 is not supported. You must <a href="https://drupal.org/node/2179269">migrate your site to Drupal 8</a> first.';
-    $this->assertRaw($text, 'Updates from schema versions prior to 8000 are prevented.');
+    $this->update_url = $GLOBALS['base_url'] . '/update.php';
+    $this->update_user = $this->drupalCreateUser(array('administer software updates', 'access site in maintenance mode'));
   }
 
   /**
@@ -102,7 +80,7 @@ function testRequirements() {
     // If there are no requirements warnings or errors, we expect to be able to
     // go through the update process uninterrupted.
     $this->drupalGet($this->update_url, array('external' => TRUE));
-    $this->drupalPostForm(NULL, array(), t('Continue'));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('No pending updates.'), 'End of update process was reached.');
     // Confirm that all caches were cleared.
     $this->assertText(t('hook_cache_flush() invoked for update_script_test.module.'), 'Caches were cleared when there were no requirements warnings or errors.');
@@ -119,8 +97,8 @@ function testRequirements() {
     $this->assertText('This is a requirements warning provided by the update_script_test module.');
     $this->clickLink('try again');
     $this->assertNoText('This is a requirements warning provided by the update_script_test module.');
-    $this->drupalPostForm(NULL, array(), t('Continue'));
-    $this->drupalPostForm(NULL, array(), 'Apply pending updates');
+    $this->clickLink(t('Continue'));
+    $this->clickLink(t('Apply pending updates'));
     $this->assertText(t('The update_script_test_update_8001() update was executed successfully.'), 'End of update process was reached.');
     // Confirm that all caches were cleared.
     $this->assertText(t('hook_cache_flush() invoked for update_script_test.module.'), 'Caches were cleared after resolving a requirements warning and applying updates.');
@@ -130,7 +108,7 @@ function testRequirements() {
     $this->assertText('This is a requirements warning provided by the update_script_test module.');
     $this->clickLink('try again');
     $this->assertNoText('This is a requirements warning provided by the update_script_test module.');
-    $this->drupalPostForm(NULL, array(), t('Continue'));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('No pending updates.'), 'End of update process was reached.');
     // Confirm that all caches were cleared.
     $this->assertText(t('hook_cache_flush() invoked for update_script_test.module.'), 'Caches were cleared after applying updates and re-running the script.');
@@ -165,7 +143,8 @@ function testThemeSystem() {
   function testNoUpdateFunctionality() {
     // Click through update.php with 'administer software updates' permission.
     $this->drupalLogin($this->update_user);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('No pending updates.'));
     $this->assertNoLink('Administration pages');
     $this->assertNoLinkByHref('update.php', 0);
@@ -175,7 +154,8 @@ function testNoUpdateFunctionality() {
     // Click through update.php with 'access administration pages' permission.
     $admin_user = $this->drupalCreateUser(array('administer software updates', 'access administration pages'));
     $this->drupalLogin($admin_user);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('No pending updates.'));
     $this->assertLink('Administration pages');
     $this->assertNoLinkByHref('update.php', 1);
@@ -197,8 +177,9 @@ function testSuccessfulUpdateFunctionality() {
 
     // Click through update.php with 'administer software updates' permission.
     $this->drupalLogin($this->update_user);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
-    $this->drupalPostForm(NULL, array(), t('Apply pending updates'));
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $this->clickLink(t('Continue'));
+    $this->clickLink(t('Apply pending updates'));
 
     // Verify that updates were completed successfully.
     $this->assertText('Updates were attempted.');
@@ -229,10 +210,11 @@ function testSuccessfulUpdateFunctionality() {
 
     // Click through update.php with 'access administration pages' and
     // 'access site reports' permissions.
-    $admin_user = $this->drupalCreateUser(array('administer software updates', 'access administration pages', 'access site reports'));
+    $admin_user = $this->drupalCreateUser(array('administer software updates', 'access administration pages', 'access site reports', 'access site in maintenance mode'));
     $this->drupalLogin($admin_user);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
-    $this->drupalPostForm(NULL, array(), t('Apply pending updates'));
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $this->clickLink(t('Continue'));
+    $this->clickLink(t('Apply pending updates'));
     $this->assertText('Updates were attempted.');
     $this->assertLink('logged');
     $this->assertLink('Administration pages');
diff --git a/core/modules/system/src/Tests/Update/UpdatesWith7x.php b/core/modules/system/src/Tests/Update/UpdatesWith7x.php
index 4d85f9d..1350df5 100644
--- a/core/modules/system/src/Tests/Update/UpdatesWith7x.php
+++ b/core/modules/system/src/Tests/Update/UpdatesWith7x.php
@@ -42,7 +42,7 @@ public static function getInfo() {
   function setUp() {
     parent::setUp();
     require_once DRUPAL_ROOT . '/core/includes/update.inc';
-    $this->update_url = $GLOBALS['base_url'] . '/core/update.php';
+    $this->update_url = $GLOBALS['base_url'] . '/update.php';
     $this->update_user = $this->drupalCreateUser(array('administer software updates'));
   }
 
@@ -57,7 +57,8 @@ function testWith7x() {
 
     // Click through update.php with 'administer software updates' permission.
     $this->drupalLogin($this->update_user);
-    $this->drupalPostForm($this->update_url, array(), t('Continue'), array('external' => TRUE));
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $this->clickLink(t('Continue'));
     $this->assertText(t('Some of the pending updates cannot be applied because their dependencies were not met.'));
   }
 }