diff --git a/core/includes/common.inc b/core/includes/common.inc
index 0b1774696fb..240f644a154 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -7797,9 +7797,10 @@ function archiver_get_archiver($file) {
  * file system, for example to update modules that have newer releases, or to
  * install a new theme.
  *
- * @return
+ * @return array
  *   The Drupal Updater class registry.
  *
+ * @see Drupal\Core\Updater\Updater
  * @see hook_updater_info()
  * @see hook_updater_info_alter()
  */
diff --git a/core/includes/updater.inc b/core/includes/updater.inc
deleted file mode 100644
index d4f99e9741a..00000000000
--- a/core/includes/updater.inc
+++ /dev/null
@@ -1,427 +0,0 @@
-<?php
-
-/**
- * @file
- * Classes used for updating various files in the Drupal webroot. These
- * classes use a FileTransfer object to actually perform the operations.
- * Normally, the FileTransfer is provided when the site owner is redirected to
- * authorize.php as part of a multistep process.
- */
-
-/**
- * Interface for a class which can update a Drupal project.
- *
- * An Updater currently serves the following purposes:
- *   - It can take a given directory, and determine if it can operate on it.
- *   - It can move the contents of that directory into the appropriate place
- *     on the system using FileTransfer classes.
- *   - It can return a list of "next steps" after an update or install.
- *   - In the future, it will most likely perform some of those steps as well.
- */
-interface DrupalUpdaterInterface {
-
-  /**
-   * Checks if the project is installed.
-   *
-   * @return bool
-   */
-  public function isInstalled();
-
-  /**
-   * Returns the system name of the project.
-   *
-   * @param string $directory
-   *  A directory containing a project.
-   */
-  public static function getProjectName($directory);
-
-  /**
-   * @return string
-   *   An absolute path to the default install location.
-   */
-  public function getInstallDirectory();
-
-  /**
-   * Determine if the Updater can handle the project provided in $directory.
-   *
-   * @todo: Provide something more rational here, like a project spec file.
-   *
-   * @param string $directory
-   *
-   * @return bool
-   *   TRUE if the project is installed, FALSE if not.
-   */
-  public static function canUpdateDirectory($directory);
-
-  /**
-   * Actions to run after an install has occurred.
-   */
-  public function postInstall();
-
-  /**
-   * Actions to run after an update has occurred.
-   */
-  public function postUpdate();
-}
-
-/**
- * Base class for Updaters used in Drupal.
- */
-class Updater {
-
-  /**
-   * @var string $source Directory to install from.
-   */
-  public $source;
-
-  public function __construct($source) {
-    $this->source = $source;
-    $this->name = self::getProjectName($source);
-    $this->title = self::getProjectTitle($source);
-  }
-
-  /**
-   * Return an Updater of the appropriate type depending on the source.
-   *
-   * If a directory is provided which contains a module, will return a
-   * ModuleUpdater.
-   *
-   * @param string $source
-   *   Directory of a Drupal project.
-   *
-   * @return Updater
-   */
-  public static function factory($source) {
-    if (is_dir($source)) {
-      $updater = self::getUpdaterFromDirectory($source);
-    }
-    else {
-      throw new UpdaterException(t('Unable to determine the type of the source directory.'));
-    }
-    return new $updater($source);
-  }
-
-  /**
-   * Determine which Updater class can operate on the given directory.
-   *
-   * @param string $directory
-   *   Extracted Drupal project.
-   *
-   * @return string
-   *   The class name which can work with this project type.
-   */
-  public static function getUpdaterFromDirectory($directory) {
-    // Gets a list of possible implementing classes.
-    $updaters = drupal_get_updaters();
-    foreach ($updaters as $updater) {
-      $class = $updater['class'];
-      if (call_user_func(array($class, 'canUpdateDirectory'), $directory)) {
-        return $class;
-      }
-    }
-    throw new UpdaterException(t('Cannot determine the type of project.'));
-  }
-
-  /**
-   * Figure out what the most important (or only) info file is in a directory.
-   *
-   * Since there is no enforcement of which info file is the project's "main"
-   * info file, this will get one with the same name as the directory, or the
-   * first one it finds.  Not ideal, but needs a larger solution.
-   *
-   * @param string $directory
-   *   Directory to search in.
-   *
-   * @return string
-   *   Path to the info file.
-   */
-  public static function findInfoFile($directory) {
-    $info_files = file_scan_directory($directory, '/.*\.info$/');
-    if (!$info_files) {
-      return FALSE;
-    }
-    foreach ($info_files as $info_file) {
-      if (drupal_substr($info_file->filename, 0, -5) == drupal_basename($directory)) {
-        // Info file Has the same name as the directory, return it.
-        return $info_file->uri;
-      }
-    }
-    // Otherwise, return the first one.
-    $info_file = array_shift($info_files);
-    return $info_file->uri;
-  }
-
-  /**
-   * Get the name of the project directory (basename).
-   *
-   * @todo: It would be nice, if projects contained an info file which could
-   *        provide their canonical name.
-   *
-   * @param string $directory
-   *
-   * @return string
-   *   The name of the project.
-   */
-  public static function getProjectName($directory) {
-    return drupal_basename($directory);
-  }
-
-  /**
-   * Return the project name from a Drupal info file.
-   *
-   * @param string $directory
-   *   Directory to search for the info file.
-   *
-   * @return string
-   *   The title of the project.
-   */
-  public static function getProjectTitle($directory) {
-    $info_file = self::findInfoFile($directory);
-    $info = drupal_parse_info_file($info_file);
-    if (empty($info)) {
-      throw new UpdaterException(t('Unable to parse info file: %info_file.', array('%info_file' => $info_file)));
-    }
-    if (empty($info['name'])) {
-      throw new UpdaterException(t("The info file (%info_file) does not define a 'name' attribute.", array('%info_file' => $info_file)));
-    }
-    return $info['name'];
-  }
-
-  /**
-   * Store the default parameters for the Updater.
-   *
-   * @param array $overrides
-   *   An array of overrides for the default parameters.
-   *
-   * @return array
-   *   An array of configuration parameters for an update or install operation.
-   */
-  protected function getInstallArgs($overrides = array()) {
-    $args = array(
-      'make_backup' => FALSE,
-      'install_dir' => $this->getInstallDirectory(),
-      'backup_dir'  => $this->getBackupDir(),
-    );
-    return array_merge($args, $overrides);
-  }
-
-  /**
-   * Updates a Drupal project, returns a list of next actions.
-   *
-   * @param FileTransfer $filetransfer
-   *   Object that is a child of FileTransfer. Used for moving files
-   *   to the server.
-   * @param array $overrides
-   *   An array of settings to override defaults; see self::getInstallArgs().
-   *
-   * @return array
-   *   An array of links which the user may need to complete the update
-   */
-  public function update(&$filetransfer, $overrides = array()) {
-    try {
-      // Establish arguments with possible overrides.
-      $args = $this->getInstallArgs($overrides);
-
-      // Take a Backup.
-      if ($args['make_backup']) {
-        $this->makeBackup($args['install_dir'], $args['backup_dir']);
-      }
-
-      if (!$this->name) {
-        // This is bad, don't want to delete the install directory.
-        throw new UpdaterException(t('Fatal error in update, cowardly refusing to wipe out the install directory.'));
-      }
-
-      // Make sure the installation parent directory exists and is writable.
-      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);
-
-      // Note: If the project is installed in sites/all, it will not be
-      // deleted. It will be installed in sites/default as that will override
-      // the sites/all reference and not break other sites which are using it.
-      if (is_dir($args['install_dir'] . '/' . $this->name)) {
-        // Remove the existing installed file.
-        $filetransfer->removeDirectory($args['install_dir'] . '/' . $this->name);
-      }
-
-      // Copy the directory in place.
-      $filetransfer->copyDirectory($this->source, $args['install_dir']);
-
-      // Make sure what we just installed is readable by the web server.
-      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);
-
-      // Run the updates.
-      // @TODO: decide if we want to implement this.
-      $this->postUpdate();
-
-      // For now, just return a list of links of things to do.
-      return $this->postUpdateTasks();
-    }
-    catch (FileTransferException $e) {
-      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));
-    }
-  }
-
-  /**
-   * Installs a Drupal project, returns a list of next actions.
-   *
-   * @param FileTransfer $filetransfer
-   *   Object that is a child of FileTransfer.
-   * @param array $overrides
-   *   An array of settings to override defaults; see self::getInstallArgs().
-   *
-   * @return array
-   *   An array of links which the user may need to complete the install.
-   */
-  public function install(&$filetransfer, $overrides = array()) {
-    try {
-      // Establish arguments with possible overrides.
-      $args = $this->getInstallArgs($overrides);
-
-      // Make sure the installation parent directory exists and is writable.
-      $this->prepareInstallDirectory($filetransfer, $args['install_dir']);
-
-      // Copy the directory in place.
-      $filetransfer->copyDirectory($this->source, $args['install_dir']);
-
-      // Make sure what we just installed is readable by the web server.
-      $this->makeWorldReadable($filetransfer, $args['install_dir'] . '/' . $this->name);
-
-      // Potentially enable something?
-      // @TODO: decide if we want to implement this.
-      $this->postInstall();
-      // For now, just return a list of links of things to do.
-      return $this->postInstallTasks();
-    }
-    catch (FileTransferException $e) {
-      throw new UpdaterFileTransferException(t('File Transfer failed, reason: !reason', array('!reason' => strtr($e->getMessage(), $e->arguments))));
-    }
-  }
-
-  /**
-   * Make sure the installation parent directory exists and is writable.
-   *
-   * @param FileTransfer $filetransfer
-   *   Object which is a child of FileTransfer.
-   * @param string $directory
-   *   The installation directory to prepare.
-   */
-  public function prepareInstallDirectory(&$filetransfer, $directory) {
-    // Make the parent dir writable if need be and create the dir.
-    if (!is_dir($directory)) {
-      $parent_dir = dirname($directory);
-      if (!is_writable($parent_dir)) {
-        @chmod($parent_dir, 0755);
-        // It is expected that this will fail if the directory is owned by the
-        // FTP user. If the FTP user == web server, it will succeed.
-        try {
-          $filetransfer->createDirectory($directory);
-          $this->makeWorldReadable($filetransfer, $directory);
-        }
-        catch (FileTransferException $e) {
-          // Probably still not writable. Try to chmod and do it again.
-          // @todo: Make a new exception class so we can catch it differently.
-          try {
-            $old_perms = substr(sprintf('%o', fileperms($parent_dir)), -4);
-            $filetransfer->chmod($parent_dir, 0755);
-            $filetransfer->createDirectory($directory);
-            $this->makeWorldReadable($filetransfer, $directory);
-            // Put the permissions back.
-            $filetransfer->chmod($parent_dir, intval($old_perms, 8));
-          }
-          catch (FileTransferException $e) {
-            $message = t($e->getMessage(), $e->arguments);
-            $throw_message = t('Unable to create %directory due to the following: %reason', array('%directory' => $directory, '%reason' => $message));
-            throw new UpdaterException($throw_message);
-          }
-        }
-        // Put the parent directory back.
-        @chmod($parent_dir, 0555);
-      }
-    }
-  }
-
-  /**
-   * Ensure that a given directory is world readable.
-   *
-   * @param FileTransfer $filetransfer
-   *   Object which is a child of FileTransfer.
-   * @param string $path
-   *   The file path to make world readable.
-   * @param bool $recursive
-   *   If the chmod should be applied recursively.
-   */
-  public function makeWorldReadable(&$filetransfer, $path, $recursive = TRUE) {
-    if (!is_executable($path)) {
-      // Set it to read + execute.
-      $new_perms = substr(sprintf('%o', fileperms($path)), -4, -1) . "5";
-      $filetransfer->chmod($path, intval($new_perms, 8), $recursive);
-    }
-  }
-
-  /**
-   * Perform a backup.
-   *
-   * @todo Not implemented.
-   */
-  public function makeBackup(&$filetransfer, $from, $to) {
-  }
-
-  /**
-   * Return the full path to a directory where backups should be written.
-   */
-  public function getBackupDir() {
-    return file_stream_wrapper_get_instance_by_scheme('temporary')->getDirectoryPath();
-  }
-
-  /**
-   * Perform actions after new code is updated.
-   */
-  public function postUpdate() {
-  }
-
-  /**
-   * Perform actions after installation.
-   */
-  public function postInstall() {
-  }
-
-  /**
-   * Return an array of links to pages that should be visited post operation.
-   *
-   * @return array
-   *   Links which provide actions to take after the install is finished.
-   */
-  public function postInstallTasks() {
-    return array();
-  }
-
-  /**
-   * Return an array of links to pages that should be visited post operation.
-   *
-   * @return array
-   *   Links which provide actions to take after the update is finished.
-   */
-  public function postUpdateTasks() {
-    return array();
-  }
-}
-
-/**
- * Exception class for the Updater class hierarchy.
- *
- * This is identical to the base Exception class, we just give it a more
- * specific name so that call sites that want to tell the difference can
- * specifically catch these exceptions and treat them differently.
- */
-class UpdaterException extends Exception {
-}
-
-/**
- * Child class of UpdaterException that indicates a FileTransfer exception.
- *
- * We have to catch FileTransfer exceptions and wrap those in t(), since
- * FileTransfer is so low-level that it doesn't use any Drupal APIs and none
- * of the strings are translated.
- */
-class UpdaterFileTransferException extends UpdaterException {
-}
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index eac29fefcf2..e1d5298eab4 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -4042,9 +4042,9 @@ function hook_batch_alter(&$batch) {
 /**
  * Provide information on Updaters (classes that can update Drupal).
  *
- * An Updater is a class that knows how to update various parts of the Drupal
- * file system, for example to update modules that have newer releases, or to
- * install a new theme.
+ * Drupal\Core\Updater\Updater is a class that knows how to update various parts
+ * of the Drupal file system, for example to update modules that have newer
+ * releases, or to install a new theme.
  *
  * @return
  *   An associative array of information about the updater(s) being provided.
@@ -4066,12 +4066,12 @@ function hook_batch_alter(&$batch) {
 function hook_updater_info() {
   return array(
     'module' => array(
-      'class' => 'ModuleUpdater',
+      'class' => 'Drupal\Core\Updater\Module',
       'name' => t('Update modules'),
       'weight' => 0,
     ),
     'theme' => array(
-      'class' => 'ThemeUpdater',
+      'class' => 'Drupal\Core\Updater\Theme',
       'name' => t('Update themes'),
       'weight' => 0,
     ),
diff --git a/core/modules/system/system.info b/core/modules/system/system.info
index c394849e73b..d95d5611f10 100644
--- a/core/modules/system/system.info
+++ b/core/modules/system/system.info
@@ -7,7 +7,6 @@ files[] = system.archiver.inc
 files[] = system.mail.inc
 files[] = system.queue.inc
 files[] = system.tar.inc
-files[] = system.updater.inc
 files[] = system.test
 required = TRUE
 configure = admin/config/system
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 14e73f5a45a..469f996655d 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1862,12 +1862,12 @@ function system_authorized_batch_process() {
 function system_updater_info() {
   return array(
     'module' => array(
-      'class' => 'ModuleUpdater',
+      'class' => 'Drupal\Core\Updater\Module',
       'name' => t('Update modules'),
       'weight' => 0,
     ),
     'theme' => array(
-      'class' => 'ThemeUpdater',
+      'class' => 'Drupal\Core\Updater\Theme',
       'name' => t('Update themes'),
       'weight' => 0,
     ),
diff --git a/core/modules/system/system.updater.inc b/core/modules/system/system.updater.inc
deleted file mode 100644
index 84c1752d3bf..00000000000
--- a/core/modules/system/system.updater.inc
+++ /dev/null
@@ -1,146 +0,0 @@
-<?php
-
-/**
- * @file
- * Subclasses of the Updater class to update Drupal core knows how to update.
- * At this time, only modules and themes are supported.
- */
-
-/**
- * Class for updating modules using FileTransfer classes via authorize.php.
- */
-class ModuleUpdater extends Updater implements DrupalUpdaterInterface {
-
-  /**
-   * Return the directory where a module should be installed.
-   *
-   * If the module is already installed, drupal_get_path() will return
-   * a valid path and we should install it there (although we need to use an
-   * absolute path, so we prepend DRUPAL_ROOT). If we're installing a new
-   * module, we always want it to go into sites/all/modules, since that's
-   * where all the documentation recommends users install their modules, and
-   * there's no way that can conflict on a multi-site installation, since
-   * the Update manager won't let you install a new module if it's already
-   * found on your system, and if there was a copy in sites/all, we'd see it.
-   */
-  public function getInstallDirectory() {
-    if ($relative_path = drupal_get_path('module', $this->name)) {
-      $relative_path = dirname($relative_path);
-    }
-    else {
-      $relative_path = 'sites/all/modules';
-    }
-    return DRUPAL_ROOT . '/' . $relative_path;
-  }
-
-  public function isInstalled() {
-    return (bool) drupal_get_path('module', $this->name);
-  }
-
-  public static function canUpdateDirectory($directory) {
-    if (file_scan_directory($directory, '/.*\.module$/')) {
-      return TRUE;
-    }
-    return FALSE;
-  }
-
-  public static function canUpdate($project_name) {
-    return (bool) drupal_get_path('module', $project_name);
-  }
-
-  /**
-   * Return available database schema updates one a new version is installed.
-   */
-  public function getSchemaUpdates() {
-    require_once DRUPAL_ROOT . '/core/includes/install.inc';
-    require_once DRUPAL_ROOT . '/core/includes/update.inc';
-
-    if (_update_get_project_type($project) != 'module') {
-      return array();
-    }
-    module_load_include('install', $project);
-
-    if (!$updates = drupal_get_schema_versions($project)) {
-      return array();
-    }
-    $updates_to_run = array();
-    $modules_with_updates = update_get_update_list();
-    if ($updates = $modules_with_updates[$project]) {
-      if ($updates['start']) {
-        return $updates['pending'];
-      }
-    }
-    return array();
-  }
-
-  public function postInstallTasks() {
-    return array(
-      l(t('Enable newly added modules'), 'admin/modules'),
-      l(t('Administration pages'), 'admin'),
-    );
-  }
-
-  public function postUpdateTasks() {
-    // We don't want to check for DB updates here, we do that once for all
-    // updated modules on the landing page.
-  }
-
-}
-
-/**
- * Class for updating themes using FileTransfer classes via authorize.php.
- */
-class ThemeUpdater extends Updater implements DrupalUpdaterInterface {
-
-  /**
-   * Return the directory where a theme should be installed.
-   *
-   * If the theme is already installed, drupal_get_path() will return
-   * a valid path and we should install it there (although we need to use an
-   * absolute path, so we prepend DRUPAL_ROOT). If we're installing a new
-   * theme, we always want it to go into sites/all/themes, since that's
-   * where all the documentation recommends users install their themes, and
-   * there's no way that can conflict on a multi-site installation, since
-   * the Update manager won't let you install a new theme if it's already
-   * found on your system, and if there was a copy in sites/all, we'd see it.
-   */
-  public function getInstallDirectory() {
-    if ($relative_path = drupal_get_path('theme', $this->name)) {
-      $relative_path = dirname($relative_path);
-    }
-    else {
-      $relative_path = 'sites/all/themes';
-    }
-    return DRUPAL_ROOT . '/' . $relative_path;
-  }
-
-  public function isInstalled() {
-    return (bool) drupal_get_path('theme', $this->name);
-  }
-
-  static function canUpdateDirectory($directory) {
-    // This is a lousy test, but don't know how else to confirm it is a theme.
-    if (file_scan_directory($directory, '/.*\.module$/')) {
-      return FALSE;
-    }
-    return TRUE;
-  }
-
-  public static function canUpdate($project_name) {
-    return (bool) drupal_get_path('theme', $project_name);
-  }
-
-  public function postInstall() {
-    // Update the system table.
-    clearstatcache();
-    system_rebuild_theme_data();
-
-  }
-
-  public function postInstallTasks() {
-    return array(
-      l(t('Enable newly added themes'), 'admin/appearance'),
-      l(t('Administration pages'), 'admin'),
-    );
-  }
-}
diff --git a/core/modules/update/update.authorize.inc b/core/modules/update/update.authorize.inc
index 35dde0eb4fc..48dfd353f21 100644
--- a/core/modules/update/update.authorize.inc
+++ b/core/modules/update/update.authorize.inc
@@ -9,6 +9,8 @@
  * the rest of the update module code.
  */
 
+use Drupal\Core\Updater\UpdaterException;
+
 /**
  * Callback invoked by authorize.php to update existing projects.
  *
@@ -19,7 +21,8 @@
  *   A nested array of projects to install into the live webroot, keyed by
  *   project name. Each subarray contains the following keys:
  *   - 'project': The canonical project short name.
- *   - 'updater_name': The name of the Updater class to use for this project.
+ *   - 'updater_name': The name of the Drupal\Core\Updater\Updater class to use
+ *     for this project.
  *   - 'local_url': The locally installed location of new code to update with.
  */
 function update_authorize_run_update($filetransfer, $projects) {
@@ -58,7 +61,8 @@ function update_authorize_run_update($filetransfer, $projects) {
  * @param string $project
  *   The canonical project short name (e.g. {system}.name).
  * @param string $updater_name
- *   The name of the Updater class to use for installing this project.
+ *   The name of the Drupal\Core\Updater\Updater class to use for installing
+ *   this project.
  * @param string $local_url
  *   The URL to the locally installed temp directory where the project has
  *   already been downloaded and extracted into.
@@ -95,7 +99,8 @@ function update_authorize_run_install($filetransfer, $project, $updater_name, $l
  * @param string $project
  *   The canonical short name of the project being installed.
  * @param string $updater_name
- *   The name of the Updater class to use for installing this project.
+ *   The name of the Drupal\Core\Updater\Updater class to use for installing
+ *   this project.
  * @param string $local_url
  *   The URL to the locally installed temp directory where the project has
  *   already been downloaded and extracted into.
diff --git a/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
index f56dd0b1585..82b48f3a68b 100644
--- a/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -35,6 +35,8 @@
  * into the live web root.
  */
 
+use Drupal\Core\Updater\Updater;
+
 /**
  * @defgroup update_manager_update Update manager: update
  * @{
@@ -393,9 +395,10 @@ function update_manager_update_ready_form($form, &$form_state) {
  *
  * If the site administrator requested that the site is put offline during the
  * update, do so now. Otherwise, pull information about all the required
- * updates out of the SESSION, figure out what Updater class is needed for
- * each one, generate an array of update operations to perform, and hand it
- * all off to system_authorized_init(), then redirect to authorize.php.
+ * updates out of the SESSION, figure out what Drupal\Core\Updater\Updater class
+ * is needed for each one, generate an array of update operations to perform,
+ * and hand it all off to system_authorized_init(), then redirect to
+ * authorize.php.
  *
  * @see update_authorize_run_update()
  * @see system_authorized_init()
@@ -600,10 +603,10 @@ function update_manager_install_form_validate($form, &$form_state) {
  * Either downloads the file specified in the URL to a temporary cache, or
  * uploads the file attached to the form, then attempts to extract the archive
  * into a temporary location and verify it. Instantiate the appropriate
- * Updater class for this project and make sure it is not already installed in
- * the live webroot. If everything is successful, setup an operation to run
- * via authorize.php which will copy the extracted files from the temporary
- * location into the live site.
+ * Drupal\Core\Updater\Updater class for this project and make sure it is not
+ * already installed in the live webroot. If everything is successful, setup an
+ * operation to run via authorize.php which will copy the extracted files from
+ * the temporary location into the live site.
  *
  * @see update_authorize_run_install()
  * @see system_authorized_init()