diff -u b/core/modules/comment/comment.module b/core/modules/comment/comment.module
--- b/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -2212,7 +2212,7 @@
         $destination = array('destination' => "node/$node->nid#comment-form");
       }
 
-      if (config('user.settings')->get('register')) {
+      if (config('user.settings')->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY) {
         // Users can register themselves.
         return t('<a href="@login">Log in</a> or <a href="@register">register</a> to post comments', array('@login' => url('user/login', array('query' => $destination)), '@register' => url('user/register', array('query' => $destination))));
       }
diff -u b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
--- b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
@@ -648,7 +648,7 @@
         if (!$this->loggedInUser) {
           if (user_access('post comments', $this->web_user)) {
             // The note depends on whether users are actually able to register.
-            if ($info['user_register']) {
+            if ($info['user_register'] != USER_REGISTER_ADMINISTRATORS_ONLY) {
               $this->assertText('Log in or register to post comments');
             }
             else {
reverted:
--- b/core/modules/contact/config/contact.settings.yml
+++ /dev/null
@@ -1 +0,0 @@
-user_contact_default_enabled: '1'
reverted:
--- b/core/modules/contact/contact.install
+++ a/core/modules/contact/contact.install
@@ -87,17 +87,7 @@
  * Implements hook_uninstall().
  */
 function contact_uninstall() {
+  variable_del('contact_default_status');
   variable_del('contact_threshold_limit');
   variable_del('contact_threshold_window');
 }
-
-/**
- * Moves contact setting from variable to config.
- *
- * @ingroup config_upgrade
- */
-function contact_update_8000() {
-  update_variables_to_config('contact.settings', array(
-    'contact_default_status' => 'user_contact_default_enabled',
-  ));
-}
reverted:
--- b/core/modules/contact/contact.module
+++ a/core/modules/contact/contact.module
@@ -234,7 +234,7 @@
  * Implements hook_user_presave().
  */
 function contact_user_presave($account) {
+  $account->data['contact'] = isset($account->contact) ? $account->contact : variable_get('contact_default_status', 1);
-  $account->data['contact'] = isset($account->contact) ? $account->contact : config('contact.settings')->get('user_contact_default_enabled');
 }
 
 /**
@@ -250,16 +250,10 @@
     '#title' => t('Contact settings'),
     '#weight' => 0,
   );
+  $form['contact']['contact_default_status'] = array(
-  $form['contact']['user_contact_default_enabled'] = array(
     '#type' => 'checkbox',
     '#title' => t('Enable the personal contact form by default for new users.'),
     '#description' => t('Changing this setting will not affect existing users.'),
+    '#default_value' => variable_get('contact_default_status', 1),
-    '#default_value' => config('contact.settings')->get('user_contact_default_enabled'),
   );
-  // Add submit handler to save contact configuration.
-  array_unshift($form['#submit'], 'contact_form_user_admin_settings_submit');
-}
-
-function contact_form_user_admin_settings_submit($form, &$form_state) {
-  config('contact.settings')->set('user_contact_default_enabled', $form_state['values']['user_contact_default_enabled'])->save();
 }
reverted:
--- b/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php
+++ a/core/modules/contact/lib/Drupal/contact/Tests/ContactPersonalTest.php
@@ -32,7 +32,7 @@
     $this->admin_user = $this->drupalCreateUser(array('administer contact forms', 'administer users'));
 
     // Create some normal users with their contact forms enabled by default.
+    variable_set('contact_default_status', TRUE);
-    config('contact.settings')->set('user_contact_default_enabled', 1)->save();
     $this->web_user = $this->drupalCreateUser(array('access user contact forms'));
     $this->contact_user = $this->drupalCreateUser();
   }
@@ -84,7 +84,7 @@
 
     // Disable the personal contact form.
     $this->drupalLogin($this->admin_user);
+    $edit = array('contact_default_status' => FALSE);
-    $edit = array('user_contact_default_enabled' => FALSE);
     $this->drupalPost('admin/config/people/accounts', $edit, t('Save configuration'));
     $this->assertText(t('The configuration options have been saved.'), t('Setting successfully saved.'));
     $this->drupalLogout();
reverted:
--- b/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php
+++ a/core/modules/contact/lib/Drupal/contact/Tests/ContactSitewideTest.php
@@ -39,7 +39,7 @@
 
     // Set settings.
     $edit = array();
+    $edit['contact_default_status'] = TRUE;
-    $edit['user_contact_default_enabled'] = TRUE;
     $this->drupalPost('admin/config/people/accounts', $edit, t('Save configuration'));
     $this->assertText(t('The configuration options have been saved.'), t('Setting successfully saved.'));
 
diff -u b/core/modules/openid/lib/Drupal/openid/Tests/OpenIDRegistrationTest.php b/core/modules/openid/lib/Drupal/openid/Tests/OpenIDRegistrationTest.php
--- b/core/modules/openid/lib/Drupal/openid/Tests/OpenIDRegistrationTest.php
+++ b/core/modules/openid/lib/Drupal/openid/Tests/OpenIDRegistrationTest.php
@@ -29,7 +29,7 @@
    * Test OpenID auto-registration with e-mail verification enabled.
    */
   function testRegisterUserWithEmailVerification() {
-    config('user.settings')->set('mail.verification', TRUE)->save();
+    config('user.settings')->set('mail_verification', TRUE)->save();
     variable_get('configurable_timezones', 1);
     variable_set('date_default_timezone', 'Europe/Brussels');
 
@@ -86,7 +86,7 @@
    * Test OpenID auto-registration with e-mail verification disabled.
    */
   function testRegisterUserWithoutEmailVerification() {
-    config('user.settings')->set('mail.verification', FALSE)->save();
+    config('user.settings')->set('mail_verification', FALSE)->save();
     variable_get('configurable_timezones', 1);
     variable_set('date_default_timezone', 'Europe/Brussels');
 
@@ -218,7 +218,7 @@
    * but no SREG.
    */
   function testRegisterUserWithAXButNoSREG() {
-    config('user.settings')->set('mail.verification', FALSE)->save();
+    config('user.settings')->set('mail_verification', FALSE)->save();
     variable_set('date_default_timezone', 'Europe/Brussels');
 
     // Tell openid_test.module to respond with these AX fields.
diff -u b/core/modules/openid/openid.module b/core/modules/openid/openid.module
--- b/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -86,7 +86,7 @@
 function openid_user_insert($account) {
   if (!empty($account->openid_claimed_id)) {
     // The user has registered after trying to log in via OpenID.
-    if (config('user.settings')->get('mail.verification')) {
+    if (config('user.settings')->get('mail_verification')) {
       drupal_set_message(t('Once you have verified your e-mail address, you may log in via OpenID.'));
     }
     user_set_authmaps($account, array('authname_openid' => $account->openid_claimed_id));
@@ -218,7 +218,7 @@
 
     // If email verification is off, hide the password field and just fill
     // with random password to avoid confusion.
-    if (!config('user.settings')->get('mail.verification')) {
+    if (!config('user.settings')->get('mail_verification')) {
       $form['account']['pass']['#type'] = 'hidden';
       $form['account']['pass']['#value'] = user_password();
     }
@@ -708,7 +708,7 @@
 
   $account = user_external_load($identity);
   if (isset($account->uid)) {
-    if (!config('user.settings')->get('mail.verification') || $account->login) {
+    if (!config('user.settings')->get('mail_verification') || $account->login) {
       // Check if user is blocked.
       $state['values']['name'] = $account->name;
       user_login_name_validate(array(), $state);
@@ -724,7 +724,7 @@
     // Let other modules act on OpenID login
     module_invoke_all('openid_response', $response, $account);
   }
-  elseif (config('user.settings')->get('register')) {
+  elseif (config('user.settings')->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY) {
     // Register new user.
 
     // Save response for use in openid_form_user_register_form_alter().
diff -u b/core/modules/user/config/user.settings.yml b/core/modules/user/config/user.settings.yml
--- b/core/modules/user/config/user.settings.yml
+++ b/core/modules/user/config/user.settings.yml
@@ -2,8 +2,8 @@
-admin_role: 0
+admin_role: ''
 register: visitors
 signatures: '0'
-mail:
-  status_activated_notify: '1'
-  status_blocked_notify: '0'
-  status_cancelled_notify: '0'
-  verification: '1'
+notify:
+  activated: '1'
+  blocked: '0'
+  cancelled: '0'
+mail_verification: '1'
diff -u b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
--- b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserRegistrationTest.php
@@ -25,7 +25,7 @@
   function testRegistrationWithEmailVerification() {
     $config = config('user.settings');
     // Require e-mail verification.
-    $config->set('mail.verification', TRUE)->save();
+    $config->set('mail_verification', TRUE)->save();
 
     // Set registration to administrator only.
     $config->set('register', USER_REGISTER_ADMINISTRATORS_ONLY)->save();
@@ -56,11 +56,13 @@
 
   function testRegistrationWithoutEmailVerification() {
     $config = config('user.settings');
-    // Don't require e-mail verification.
-    $config->set('mail.verification', FALSE)->save();
+    // Don't require e-mail verification and allow registration by site visitors
+    // without administrator approval.
+    $config
+      ->set('mail_verification', FALSE)
+      ->set('register', USER_REGISTER_VISITORS)
+      ->save();
 
-    // Allow registration by site visitors without administrator approval.
-    $config->set('register', USER_REGISTER_VISITORS)->save();
     $edit = array();
     $edit['name'] = $name = $this->randomName();
     $edit['mail'] = $mail = $edit['name'] . '@example.com';
@@ -115,11 +117,10 @@
   }
 
   function testRegistrationEmailDuplicates() {
-
-    // Don't require e-mail verification.
-    // Then, allow registration by site visitors without administrator approval.
+    // Don't require e-mail verification and allow registration by site visitors
+    // without administrator approval.
     config('user.settings')
-      ->set('mail.verification', FALSE)
+      ->set('mail_verification', FALSE)
       ->set('register', USER_REGISTER_VISITORS)
       ->save();
 
@@ -142,12 +143,12 @@
   }
 
   function testRegistrationDefaultValues() {
-    // Allow registration by site visitors without administrator approval.
-    // Then, don't require e-mail verification.
     $config = config('user.settings');
+    // Don't require e-mail verification and allow registration by site visitors
+    // without administrator approval.
     $config
+      ->set('mail_verification', FALSE)
       ->set('register', USER_REGISTER_VISITORS)
-      ->set('mail.verification', FALSE)
       ->save();
 
     // Set the default timezone to Brussels.
diff -u b/core/modules/user/user.admin.inc b/core/modules/user/user.admin.inc
--- b/core/modules/user/user.admin.inc
+++ b/core/modules/user/user.admin.inc
@@ -257,7 +257,7 @@
  * Form builder; Configure user settings for this site.
  *
  * @ingroup forms
- * @see system_config_form()
+ * @see user_admin_settings_submit()
  */
 function user_admin_settings($form, &$form_state) {
   $config = config('user.settings');
@@ -313,7 +313,7 @@
   $form['registration_cancellation']['user_email_verification'] = array(
     '#type' => 'checkbox',
     '#title' => t('Require e-mail verification when a visitor creates an account.'),
-    '#default_value' => $config->get('mail.verification'),
+    '#default_value' => $config->get('mail_verification'),
     '#description' => t('New users will be required to validate their e-mail address prior to logging into the site, and will be assigned a system-generated password. With this setting disabled, users will be logged in immediately upon registering, and may select their own passwords during registration.')
   );
   module_load_include('inc', 'user', 'user.pages');
@@ -525,7 +525,7 @@
   $form['email_activated']['user_mail_status_activated_notify'] = array(
     '#type' => 'checkbox',
     '#title' => t('Notify user when account is activated.'),
-    '#default_value' => $config->get('mail.status_activated_notify'),
+    '#default_value' => $config->get('notify.status_activated'),
   );
   $form['email_activated']['settings'] = array(
     '#type' => 'container',
@@ -560,7 +560,7 @@
   $form['email_blocked']['user_mail_status_blocked_notify'] = array(
     '#type' => 'checkbox',
     '#title' => t('Notify user when account is blocked.'),
-    '#default_value' => $config->get('mail.status_blocked_notify'),
+    '#default_value' => $config->get('notify.status_blocked'),
   );
   $form['email_blocked']['settings'] = array(
     '#type' => 'container',
@@ -616,7 +616,7 @@
   $form['email_canceled']['user_mail_status_canceled_notify'] = array(
     '#type' => 'checkbox',
     '#title' => t('Notify user when account is canceled.'),
-    '#default_value' => $config->get('mail.status_canceled_notify'),
+    '#default_value' => $config->get('notify.status_canceled'),
   );
   $form['email_canceled']['settings'] = array(
     '#type' => 'container',
@@ -644,18 +644,18 @@
 }
 
 /**
- * Save account settings settings.
+ * Form submission handler for user_admin_settings().
  */
-function user_admin_settings_submit($form, $form_state) {
+function user_admin_settings_submit($form, &$form_state) {
   config('user.settings')
     ->set('anonymous', $form_state['values']['anonymous'])
     ->set('admin_role', $form_state['values']['user_admin_role'])
     ->set('register', $form_state['values']['user_register'])
-    ->set('mail.verification', $form_state['values']['user_email_verification'])
+    ->set('mail_verification', $form_state['values']['user_email_verification'])
     ->set('signatures', $form_state['values']['user_signatures'])
-    ->set('mail.status_activated_notify', $form_state['values']['user_mail_status_activated_notify'])
-    ->set('mail.status_blocked_notify', $form_state['values']['user_mail_status_blocked_notify'])
-    ->set('mail.status_canceled_notify', $form_state['values']['user_mail_status_canceled_notify'])
+    ->set('notify.status_activated', $form_state['values']['user_mail_status_activated_notify'])
+    ->set('notify.status_blocked', $form_state['values']['user_mail_status_blocked_notify'])
+    ->set('notify.status_canceled', $form_state['values']['user_mail_status_canceled_notify'])
     ->save();
 }
 
diff -u b/core/modules/user/user.install b/core/modules/user/user.install
--- b/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -452,11 +452,24 @@
     'user_admin_role' => 'admin_role',
     'user_register' => 'register',
     'user_signatures' => 'signatures',
-    'user_mail_status_activated_notify' => 'mail.status_activated_notify',
-    'user_mail_status_blocked_notify' => 'mail.status_blocked_notify',
-    'user_mail_status_cancelled_notify' => 'mail.status_cancelled_notify',
-    'user_email_verification' => 'mail.verification',
+    'user_mail_status_activated_notify' => 'notify.status_activated',
+    'user_mail_status_blocked_notify' => 'notify.status_blocked',
+    'user_mail_status_cancelled_notify' => 'notify.status_cancelled',
+    'user_email_verification' => 'mail_verification',
   ));
+
+  // Convert the user.settings:register numeric value to text value.
+  $map = array(
+    '0' => 'admin_only',
+    '1' => 'visitors',
+    '2' => 'visitors_admin_approval',
+  );
+  $config = config('user.settings');
+  $user_register = $config->get('register');
+
+  if (is_numeric($user_register) && isset($map[$user_register])) {
+    $config->set('register', $map[$user_register])->save();
+  }
 }
 
 /**
diff -u b/core/modules/user/user.module b/core/modules/user/user.module
--- b/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -22,18 +22,18 @@
 /**
  * Only administrators can create user accounts.
  */
-const USER_REGISTER_ADMINISTRATORS_ONLY = 0;
+const USER_REGISTER_ADMINISTRATORS_ONLY = 'admin_only';
 
 /**
  * Visitors can create their own accounts.
  */
-const USER_REGISTER_VISITORS = 1;
+const USER_REGISTER_VISITORS = 'visitors';
 
 /**
  * Visitors can create accounts, but they don't become active without
  * administrative approval.
  */
-const USER_REGISTER_VISITORS_ADMINISTRATIVE_APPROVAL = 2;
+const USER_REGISTER_VISITORS_ADMINISTRATIVE_APPROVAL = 'visitors_admin_approval';
 
 /**
  * Implement hook_help().
@@ -788,7 +788,7 @@
       $form['#validate'][] = 'user_validate_current_pass';
     }
   }
-  elseif (!$config->get('mail.verification') || $admin) {
+  elseif (!$config->get('mail_verification') || $admin) {
     $form['account']['pass'] = array(
       '#type' => 'password_confirm',
       '#size' => 25,
@@ -1059,7 +1059,7 @@
     '#value' => t('Log in'),
   );
   $items = array();
-  if (config('user.settings')->get('register')) {
+  if (config('user.settings')->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY) {
     $items[] = l(t('Create new account'), 'user/register', array('attributes' => array('title' => t('Create a new user account.'))));
   }
   $items[] = l(t('Request new password'), 'user/password', array('attributes' => array('title' => t('Request new password via e-mail.'))));
@@ -1420,7 +1420,7 @@
 }
 
 function user_register_access() {
-  return user_is_anonymous() && config('user.settings')->get('register');
+  return user_is_anonymous() && (config('user.settings')->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY);
 }
 
 /**
@@ -3081,7 +3081,7 @@
     '#type' => 'checkbox',
     '#title' => t('Notify user when account is canceled.'),
     '#default_value' => FALSE,
-    '#access' => config('user.settings')->get('mail.status_canceled_notify'),
+    '#access' => config('user.settings')->get('notify.status_canceled'),
     '#description' => t('When enabled, the user will receive an e-mail notification after the account has been cancelled.'),
   );
 
@@ -3300,7 +3300,7 @@
  */
 function _user_mail_notify($op, $account, $language = NULL) {
   // By default, we always notify except for canceled and blocked.
-  $notify = config('user.settings')->get('mail.' . $op . '_notify');
+  $notify = config('user.settings')->get('notify.' . $op);
   if ($notify || ($op != 'status_canceled' && $op != 'status_blocked')) {
     $params['account'] = $account;
     $language = $language ? $language : user_preferred_language($account);
@@ -3568,7 +3568,7 @@
  */
 function user_register_submit($form, &$form_state) {
   $admin = $form_state['values']['administer_users'];
-  $mail_verification = config('user.settings')->get('mail.verification');
+  $mail_verification = config('user.settings')->get('mail_verification');
 
   if (!$mail_verification || $admin) {
     $pass = $form_state['values']['pass'];
diff -u b/core/modules/user/user.pages.inc b/core/modules/user/user.pages.inc
--- b/core/modules/user/user.pages.inc
+++ b/core/modules/user/user.pages.inc
@@ -330,7 +330,7 @@
     '#description' => t('When enabled, the user must confirm the account cancellation via e-mail.'),
   );
   // Also allow to send account canceled notification mail, if enabled.
-  $default_notify = config('user.settings')->get('mail.status_canceled_notify');
+  $default_notify = config('user.settings')->get('notify.status_canceled');
   $form['user_cancel_notify'] = array(
     '#type' => 'checkbox',
     '#title' => t('Notify user when account is canceled.'),
@@ -473,7 +473,7 @@
     // Validate expiration and hashed password/login.
     if ($timestamp <= $current && $current - $timestamp < $timeout && $account->uid && $timestamp >= $account->login && $hashed_pass == user_pass_rehash($account->pass, $timestamp, $account->login)) {
       $edit = array(
-        'user_cancel_notify' => isset($account->data['user_cancel_notify']) ? $account->data['user_cancel_notify'] : config('user.settings')->get('mail.status_canceled_notify'),
+        'user_cancel_notify' => isset($account->data['user_cancel_notify']) ? $account->data['user_cancel_notify'] : config('user.settings')->get('notify.status_canceled'),
       );
       user_cancel($edit, $account->uid, $account->data['user_cancel_method']);
       // Since user_cancel() is not invoked via Form API, batch processing needs