diff --git a/core/includes/update.inc b/core/includes/update.inc
index 9dd8456..fbcd5c0 100644
--- a/core/includes/update.inc
+++ b/core/includes/update.inc
@@ -1045,7 +1045,7 @@ function update_variable_del($name) {
  *   This would migrate the value contained in variable name 'old_variable' into
  *   the data key 'new_config.sub_key' of the configuration object $config_name.
  */
-function update_variables_to_config($config_name, array $variable_map) {
+function update_variables_to_config($config_name, array $variable_map, $default_config_name = NULL) {
   // Build the new configuration object.
   // This potentially loads an existing configuration object, in case another
   // update function migrated configuration values into $config_name already.
@@ -1056,12 +1056,17 @@ function update_variables_to_config($config_name, array $variable_map) {
   $module = strtok($config_name, '.');
 
   // Load and set default configuration values.
-  $file = new FileStorage(drupal_get_path('module', $module) . '/config');
-  if (!$file->exists($config_name)) {
+  $file = new FileStorage(array('directory' => drupal_get_path('module', $module) . '/config'));
+  if ($file->exists($config_name)) {
+    $default_data = $file->read($config_name);
+  }
+  elseif ($default_config_name && $file->exists($default_config_name)) {
+    $default_data = $file->read($default_config_name);
+  }
+  else {
     throw new ConfigException("Default configuration file $config_name for $module extension not found but is required to exist.");
   }
-  $default_data = $file->read($config_name);
-
+  
   // Merge any possibly existing original data into default values.
   // Only relevant when being called repetitively on the same config object.
   if (!empty($original_data)) {
diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index 0a147b5..6380669 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -13,19 +13,19 @@ function comment_uninstall() {
   field_delete_field('comment_body');
 
   // Remove variables.
-  variable_del('comment_block_count');
+  config('comment.settings')->clear('comment_block_count');
   $node_types = array_keys(node_type_get_types());
   foreach ($node_types as $node_type) {
     field_attach_delete_bundle('comment', 'comment_node_' . $node_type);
-    variable_del('comment_' . $node_type);
-    variable_del('comment_anonymous_' . $node_type);
-    variable_del('comment_controls_' . $node_type);
-    variable_del('comment_default_mode_' . $node_type);
-    variable_del('comment_default_order_' . $node_type);
-    variable_del('comment_default_per_page_' . $node_type);
-    variable_del('comment_form_location_' . $node_type);
-    variable_del('comment_preview_' . $node_type);
-    variable_del('comment_subject_field_' . $node_type);
+    config('comment.settings.' . $node_type)->clear('comment');
+    config('comment.settings.' . $node_type)->clear('comment_anonymous');    
+    config('comment.settings.' . $node_type)->clear('comment_controls');    
+    config('comment.settings.' . $node_type)->clear('comment_default_mode');    
+    config('comment.settings.' . $node_type)->clear('comment_default_order');    
+    config('comment.settings.' . $node_type)->clear('comment_default_per_page');    
+    config('comment.settings.' . $node_type)->clear('comment_form_location');    
+    config('comment.settings.' . $node_type)->clear('comment_preview');    
+    config('comment.settings.' . $node_type)->clear('comment_subject_field');    
   }
 }
 
@@ -288,6 +288,28 @@ function comment_update_8000() {
   );
   db_change_field('comment', 'language', 'langcode', $langcode_spec);
   db_add_index('comment', 'comment_nid_langcode', array('nid', 'langcode'));
+  update_variables_to_config('comment.settings', array(
+    'comment_block_count' => 'comment_block_count',
+    'comment_maintain_node_statistics' => 'comment_maintain_node_statistics',
+    'node_cron_comments_scale' => 'node_cron_comments_scale',
+  ));
+  $node_types = db_query('SELECT DISTINCT type FROM {node_type}')->fetchCol();
+  $all_types = db_query('SELECT DISTINCT type FROM {node}')->fetchCol();
+  $extra_types = array_diff($all_types, array_keys($node_types));
+  foreach ($extra_types as $type) {
+    $node_types[$type] = $type;
+  }   
+  foreach ($node_types as $type) {
+      update_variables_to_config("comment.settings.$type", array(
+        "comment_$type" => 'comment',
+        "comment_default_mode_$type" => 'comment_default_mode',
+        "comment_default_per_page_$type" => 'comment_default_per_page',
+        "comment_anonymous_$type" => 'comment_anonymous',
+        "comment_subject_field_$type" => 'comment_subject_field',
+        "comment_form_location_$type" => 'comment_form_location',    
+        "comment_preview_$type" => 'comment_preview', 
+      ), 'comment.settings.article');
+  }   
 }
 
 /**
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 1b1dd79..af69ce4 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -189,7 +189,7 @@ function comment_field_extra_fields() {
   $return = array();
 
   foreach (node_type_get_types() as $type) {
-    if (variable_get('comment_subject_field_' . $type->type, 1) == 1) {
+    if (config('comment.settings.' . $type->type)->get('comment_subject_field') == 1) {
       $return['comment']['comment_node_' . $type->type] = array(
         'form' => array(
           'author' => array(
@@ -363,6 +363,7 @@ function comment_node_type_update($info) {
  */
 function comment_node_type_delete($info) {
   field_attach_delete_bundle('comment', 'comment_node_' . $info->type);
+  $config = config('comment.settings.' . $info->type);
   $settings = array(
     'comment',
     'comment_default_mode',
@@ -373,8 +374,9 @@ function comment_node_type_delete($info) {
     'comment_form_location',
   );
   foreach ($settings as $setting) {
-    variable_del($setting . '_' . $info->type);
+    $config->clear($setting);
   }
+  $config->save();
 }
 
  /**
@@ -458,7 +460,7 @@ function comment_block_configure($delta = '') {
   $form['comment_block_count'] = array(
     '#type' => 'select',
     '#title' => t('Number of recent comments'),
-    '#default_value' => variable_get('comment_block_count', 10),
+    '#default_value' => config('comment.settings')->get('comment_block_count'),
     '#options' => drupal_map_assoc(array(2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30)),
   );
 
@@ -469,7 +471,7 @@ function comment_block_configure($delta = '') {
  * Implements hook_block_save().
  */
 function comment_block_save($delta = '', $edit = array()) {
-  variable_set('comment_block_count', (int) $edit['comment_block_count']);
+  config('comment.settings')->set('comment_block_count', $edit['comment_block_count'])->save();
 }
 
 /**
@@ -564,8 +566,8 @@ function comment_get_recent($number = 10) {
  *   "page=X" if the page number is greater than zero; empty string otherwise.
  */
 function comment_new_page_count($num_comments, $new_replies, Node $node) {
-  $mode = variable_get('comment_default_mode_' . $node->type, COMMENT_MODE_THREADED);
-  $comments_per_page = variable_get('comment_default_per_page_' . $node->type, 50);
+  $mode = config('comment.settings.' . $node->type)->get('comment_default_mode');
+  $comments_per_page = config('comment.settings.' . $node->type)->get('comment_default_per_page');
   $pagenum = NULL;
   $flat = $mode == COMMENT_MODE_FLAT ? TRUE : FALSE;
   if ($num_comments <= $comments_per_page) {
@@ -625,7 +627,7 @@ function comment_new_page_count($num_comments, $new_replies, Node $node) {
  */
 function theme_comment_block() {
   $items = array();
-  $number = variable_get('comment_block_count', 10);
+  $number = config('comment.settings')->get('comment_block_count');
   foreach (comment_get_recent($number) as $comment) {
     $items[] = l($comment->subject, 'comment/' . $comment->cid, array('fragment' => 'comment-' . $comment->cid)) . '&nbsp;<span>' . t('@time ago', array('@time' => format_interval(REQUEST_TIME - $comment->changed))) . '</span>';
   }
@@ -679,7 +681,7 @@ function comment_node_view(Node $node, $view_mode) {
         }
       }
       if ($node->comment == COMMENT_NODE_OPEN) {
-        $comment_form_location = variable_get('comment_form_location_' . $node->type, COMMENT_FORM_BELOW);
+        $comment_form_location = config('comment.settings.' . $node->type)->get('comment_form_location');
         if (user_access('post comments')) {
           $links['comment-add'] = array(
             'title' => t('Add new comment'),
@@ -705,7 +707,7 @@ function comment_node_view(Node $node, $view_mode) {
       // But we don't want this link if we're building the node for search
       // indexing or constructing a search result excerpt.
       if ($node->comment == COMMENT_NODE_OPEN) {
-        $comment_form_location = variable_get('comment_form_location_' . $node->type, COMMENT_FORM_BELOW);
+        $comment_form_location = config('comment.settings.' . $node->type)->get('comment_form_location');
         if (user_access('post comments')) {
           // Show the "post comment" link if the form is on another page, or
           // if there are existing comments that the link will skip past.
@@ -758,13 +760,13 @@ function comment_node_view(Node $node, $view_mode) {
  */
 function comment_node_page_additions(Node $node) {
   $additions = array();
-
+  $config = config('comment.settings.' . $node->type);
   // Only attempt to render comments if the node has visible comments.
   // Unpublished comments are not included in $node->comment_count, so show
   // comments unconditionally if the user is an administrator.
   if (($node->comment_count && user_access('access comments')) || user_access('administer comments')) {
-    $mode = variable_get('comment_default_mode_' . $node->type, COMMENT_MODE_THREADED);
-    $comments_per_page = variable_get('comment_default_per_page_' . $node->type, 50);
+    $mode = $config->get('comment_default_mode');
+    $comments_per_page = $config->get('comment_default_per_page');
     if ($cids = comment_get_thread($node, $mode, $comments_per_page)) {
       $comments = comment_load_multiple($cids);
       comment_prepare_thread($comments);
@@ -775,7 +777,7 @@ function comment_node_page_additions(Node $node) {
   }
 
   // Append comment form if needed.
-  if (user_access('post comments') && $node->comment == COMMENT_NODE_OPEN && (variable_get('comment_form_location_' . $node->type, COMMENT_FORM_BELOW) == COMMENT_FORM_BELOW)) {
+  if (user_access('post comments') && $node->comment == COMMENT_NODE_OPEN && ($config->get('comment_form_location') == COMMENT_FORM_BELOW)) {
     $additions['comment_form'] = comment_add($node);
   }
 
@@ -874,6 +876,7 @@ function comment_add(Node $node, $pid = NULL) {
  * to consider the trailing "/" so we use a substring only.
  */
 function comment_get_thread(Node $node, $mode, $comments_per_page) {
+
   $query = db_select('comment', 'c')
     ->extend('Drupal\Core\Database\Query\PagerSelectExtender');
   $query->addField('c', 'cid');
@@ -898,7 +901,7 @@ function comment_get_thread(Node $node, $mode, $comments_per_page) {
     $query->condition('c.status', COMMENT_PUBLISHED);
     $count_query->condition('c.status', COMMENT_PUBLISHED);
   }
-  if ($mode === COMMENT_MODE_FLAT) {
+  if ((int)$mode === COMMENT_MODE_FLAT) {
     $query->orderBy('c.cid', 'ASC');
   }
   else {
@@ -998,7 +1001,7 @@ function comment_view(Comment $comment, Node $node, $view_mode = 'full', $langco
 
   if (empty($comment->in_preview)) {
     $prefix = '';
-    $is_threaded = isset($comment->divs) && variable_get('comment_default_mode_' . $node->type, COMMENT_MODE_THREADED) == COMMENT_MODE_THREADED;
+    $is_threaded = isset($comment->divs) && (config('comment.settings.' . $node->type)->get('comment_default_mode') == COMMENT_MODE_THREADED);
 
     // Add 'new' anchor if needed.
     if (!empty($comment->first_new)) {
@@ -1177,6 +1180,7 @@ function comment_view_multiple($comments, Node $node, $view_mode = 'full', $weig
  * Implements hook_form_FORM_ID_alter().
  */
 function comment_form_node_type_form_alter(&$form, $form_state) {
+  $config = config('comment.settings.' . $form['#node_type']->type);
   if (isset($form['type'])) {
     $form['comment'] = array(
       '#type' => 'fieldset',
@@ -1194,32 +1198,36 @@ function comment_form_node_type_form_alter(&$form, $form_state) {
     // Unlike coment_form_node_form_alter(), all of these settings are applied
     // as defaults to all new nodes. Therefore, it would be wrong to use #states
     // to hide the other settings based on the primary comment setting.
+    $comment = $config->get('comment');
     $form['comment']['comment'] = array(
       '#type' => 'select',
       '#title' => t('Default comment setting for new content'),
-      '#default_value' => variable_get('comment_' . $form['#node_type']->type, COMMENT_NODE_OPEN),
+      '#default_value' => isset($comment) ? $comment : COMMENT_NODE_OPEN,
       '#options' => array(
         COMMENT_NODE_OPEN => t('Open'),
         COMMENT_NODE_CLOSED => t('Closed'),
         COMMENT_NODE_HIDDEN => t('Hidden'),
       ),
     );
+    $comment_default_mode = $config->get('comment_default_mode');
     $form['comment']['comment_default_mode'] = array(
       '#type' => 'checkbox',
       '#title' => t('Threading'),
-      '#default_value' => variable_get('comment_default_mode_' . $form['#node_type']->type, COMMENT_MODE_THREADED),
+      '#default_value' => isset($comment_default_mode) ? $comment_default_mode : 1,
       '#description' => t('Show comment replies in a threaded list.'),
     );
+    $comment_default_per_page = $config->get('comment_default_per_page');
     $form['comment']['comment_default_per_page'] = array(
       '#type' => 'select',
       '#title' => t('Comments per page'),
-      '#default_value' => variable_get('comment_default_per_page_' . $form['#node_type']->type, 50),
+      '#default_value' => isset($comment_default_per_page) ? $comment_default_per_page : '50',
       '#options' => _comment_per_page(),
     );
+    $comment_anonymous = $config->get('comment_anonymous');
     $form['comment']['comment_anonymous'] = array(
       '#type' => 'select',
       '#title' => t('Anonymous commenting'),
-      '#default_value' => variable_get('comment_anonymous_' . $form['#node_type']->type, COMMENT_ANONYMOUS_MAYNOT_CONTACT),
+      '#default_value' => isset($comment_anonymous) ? $comment_anonymous : 0,
       '#options' => array(
         COMMENT_ANONYMOUS_MAYNOT_CONTACT => t('Anonymous posters may not enter their contact information'),
         COMMENT_ANONYMOUS_MAY_CONTACT => t('Anonymous posters may leave their contact information'),
@@ -1227,30 +1235,51 @@ function comment_form_node_type_form_alter(&$form, $form_state) {
       ),
       '#access' => user_access('post comments', drupal_anonymous_user()),
     );
+    $comment_subject_field = $config->get('comment_subject_field');
     $form['comment']['comment_subject_field'] = array(
       '#type' => 'checkbox',
       '#title' => t('Allow comment title'),
-      '#default_value' => variable_get('comment_subject_field_' . $form['#node_type']->type, 1),
+      '#default_value' => isset($comment_subject_field) ? $comment_subject_field : 1,
     );
+    $comment_form_location = $config->get('comment_form_location');
     $form['comment']['comment_form_location'] = array(
       '#type' => 'checkbox',
       '#title' => t('Show reply form on the same page as comments'),
-      '#default_value' => variable_get('comment_form_location_' . $form['#node_type']->type, COMMENT_FORM_BELOW),
+      '#default_value' => isset($comment_form_location) ? $comment_form_location : 1,
     );
+    $comment_preview = $config->get('comment_preview');
     $form['comment']['comment_preview'] = array(
       '#type' => 'radios',
       '#title' => t('Preview comment'),
-      '#default_value' => variable_get('comment_preview_' . $form['#node_type']->type, DRUPAL_OPTIONAL),
+      '#default_value' => isset($comment_preview) ? $comment_preview : DRUPAL_OPTIONAL,
       '#options' => array(
         DRUPAL_DISABLED => t('Disabled'),
         DRUPAL_OPTIONAL => t('Optional'),
         DRUPAL_REQUIRED => t('Required'),
       ),
     );
+    $form['#submit'][] = 'comment_submit_config';
   }
 }
 
 /**
+ * Implements callback submit to store conf values
+ * for the node type form().
+ */
+function comment_submit_config($form, &$form_state) {
+  config('comment.settings.' . $form['#node_type']->type)
+    ->set('comment', $form_state['values']['comment'])
+    ->set('comment_default_mode', $form_state['values']['comment_default_mode'])
+    ->set('comment_default_per_page', $form_state['values']['comment_default_per_page'])
+    ->set('comment_anonymous', $form_state['values']['comment_anonymous'])
+    ->set('comment_subject_field', $form_state['values']['comment_subject_field'])
+    ->set('comment_form_location', $form_state['values']['comment_form_location'])
+    ->set('comment_preview', $form_state['values']['comment_preview'])
+    ->save();
+  watchdog('comment', 'CMI configuration variables updated for node type %type', array('%type' => $form['#node_type']->type));
+}
+
+/**
  * Implements hook_form_BASE_FORM_ID_alter().
  */
 function comment_form_node_form_alter(&$form, $form_state) {
@@ -1300,6 +1329,7 @@ function comment_form_node_form_alter(&$form, $form_state) {
     // Also adjust the description of the "closed" option.
     $form['comment_settings']['comment'][COMMENT_NODE_CLOSED]['#description'] = t('Users cannot post comments.');
   }
+  $form['#submit'][] = 'comment_node_submit_config';
 }
 
 /**
@@ -1342,7 +1372,7 @@ function comment_node_load($nodes, $types) {
  */
 function comment_node_prepare(Node $node) {
   if (!isset($node->comment)) {
-    $node->comment = variable_get("comment_$node->type", COMMENT_NODE_OPEN);
+    $node->comment = config('comment.settings.' . $node->type)->get('comment');
   }
 }
 
@@ -1350,9 +1380,10 @@ function comment_node_prepare(Node $node) {
  * Implements hook_node_insert().
  */
 function comment_node_insert(Node $node) {
+  $config = config('comment.settings');
   // Allow bulk updates and inserts to temporarily disable the
   // maintenance of the {node_comment_statistics} table.
-  if (variable_get('comment_maintain_node_statistics', TRUE)) {
+  if ($config->get('comment_maintain_node_statistics')) {
     db_insert('node_comment_statistics')
       ->fields(array(
         'nid' => $node->nid,
@@ -1403,8 +1434,8 @@ function comment_node_update_index(Node $node, $langcode) {
   }
 
   if ($index_comments) {
-    $mode = variable_get('comment_default_mode_' . $node->type, COMMENT_MODE_THREADED);
-    $comments_per_page = variable_get('comment_default_per_page_' . $node->type, 50);
+    $mode = config('comment.settings.' . $node->type)->get('comment_default_mode');
+    $comments_per_page = config('comment.settings.' . $node->type)->get('comment_default_per_page');
     if ($node->comment && $cids = comment_get_thread($node, $mode, $comments_per_page)) {
       $comments = comment_load_multiple($cids);
       comment_prepare_thread($comments);
@@ -1420,7 +1451,7 @@ function comment_node_update_index(Node $node, $langcode) {
  */
 function comment_update_index() {
   // Store the maximum possible comments per thread (used for ranking by reply count)
-  variable_set('node_cron_comments_scale', 1.0 / max(1, db_query('SELECT MAX(comment_count) FROM {node_comment_statistics}')->fetchField()));
+  config('comment.settings')->set('node_cron_comments_scale', 1.0 / max(1, db_query('SELECT MAX(comment_count) FROM {node_comment_statistics}')->fetchField()))->save();
 }
 
 /**
@@ -1616,6 +1647,7 @@ function comment_num_new($nid, $timestamp = 0) {
  * @see comment_get_display_page()
  */
 function comment_get_display_ordinal($cid, $node_type) {
+  $config = config('comment.settings.' . $node_type);
   // Count how many comments (c1) are before $cid (c2) in display order. This is
   // the 0-based display ordinal.
   $query = db_select('comment', 'c1');
@@ -1625,7 +1657,7 @@ function comment_get_display_ordinal($cid, $node_type) {
   if (!user_access('administer comments')) {
     $query->condition('c1.status', COMMENT_PUBLISHED);
   }
-  $mode = variable_get('comment_default_mode_' . $node_type, COMMENT_MODE_THREADED);
+  $mode = $config->get('comment_default_mode');
 
   if ($mode == COMMENT_MODE_FLAT) {
     // For flat comments, cid is used for ordering comments due to
@@ -1658,8 +1690,9 @@ function comment_get_display_ordinal($cid, $node_type) {
  *   The page number.
  */
 function comment_get_display_page($cid, $node_type) {
+  $config = config('comment.settings.' . $node_type);
   $ordinal = comment_get_display_ordinal($cid, $node_type);
-  $comments_per_page = variable_get('comment_default_per_page_' . $node_type, 50);
+  $comments_per_page = $config->get('comment_default_per_page');
   return floor($ordinal / $comments_per_page);
 }
 
@@ -1816,7 +1849,7 @@ function template_preprocess_comment(&$variables) {
 function theme_comment_post_forbidden($variables) {
   $node = $variables['node'];
   global $user;
-
+  $config = config('comment.settings.' . $node->type);
   // Since this is expensive to compute, we cache it so that a page with many
   // comments only has to query the database once for all the links.
   $authenticated_post_comments = &drupal_static(__FUNCTION__, NULL);
@@ -1832,7 +1865,7 @@ function theme_comment_post_forbidden($variables) {
     if ($authenticated_post_comments) {
       // We cannot use drupal_get_destination() because these links
       // sometimes appear on /node and taxonomy listing pages.
-      if (variable_get('comment_form_location_' . $node->type, COMMENT_FORM_BELOW) == COMMENT_FORM_SEPARATE_PAGE) {
+      if ($config->get('comment_form_location') == COMMENT_FORM_SEPARATE_PAGE) {
         $destination = array('destination' => "comment/reply/$node->nid#comment-form");
       }
       else {
@@ -1860,7 +1893,7 @@ function theme_comment_post_forbidden($variables) {
 function template_preprocess_comment_wrapper(&$variables) {
   // Provide contextual information.
   $variables['node'] = $variables['content']['#node'];
-  $variables['display_mode'] = variable_get('comment_default_mode_' . $variables['node']->type, COMMENT_MODE_THREADED);
+  $variables['display_mode'] = config('comment.settings.' . $variables['node']->type)->get('comment_default_mode');
   // The comment form is optional and may not exist.
   $variables['content'] += array('comment_form' => array());
 }
@@ -2083,7 +2116,7 @@ function comment_ranking() {
       ),
       // Inverse law that maps the highest reply count on the site to 1 and 0 to 0.
       'score' => '2.0 - 2.0 / (1.0 + node_comment_statistics.comment_count * CAST(:scale AS DECIMAL))',
-      'arguments' => array(':scale' => variable_get('node_cron_comments_scale', 0)),
+      'arguments' => array(':scale' => config('comment.settings')->get('node_cron_comments_scale')),
     ),
   );
 }
diff --git a/core/modules/comment/lib/Drupal/comment/CommentFormController.php b/core/modules/comment/lib/Drupal/comment/CommentFormController.php
index f0f16c2..7c03797 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentFormController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentFormController.php
@@ -20,6 +20,7 @@ class CommentFormController extends EntityFormController {
    */
   public function form(array $form, array &$form_state, EntityInterface $comment) {
     global $user;
+    
     $language_content = language(LANGUAGE_TYPE_CONTENT);
 
     $node = node_load($comment->nid);
@@ -28,8 +29,7 @@ class CommentFormController extends EntityFormController {
     // Use #comment-form as unique jump target, regardless of node type.
     $form['#id'] = drupal_html_id('comment_form');
     $form['#theme'] = array('comment_form__node_' . $node->type, 'comment_form');
-
-    $anonymous_contact = variable_get('comment_anonymous_' . $node->type, COMMENT_ANONYMOUS_MAYNOT_CONTACT);
+    $anonymous_contact = config('comment.settings.' . $node->type)->get('comment_anonymous');
     $is_admin = (!empty($comment->cid) && user_access('administer comments'));
 
     if (!$user->uid && $anonymous_contact != COMMENT_ANONYMOUS_MAYNOT_CONTACT) {
@@ -159,7 +159,7 @@ class CommentFormController extends EntityFormController {
       '#title' => t('Subject'),
       '#maxlength' => 64,
       '#default_value' => $comment->subject,
-      '#access' => variable_get('comment_subject_field_' . $node->type, 1) == 1,
+      '#access' => config('comment.settings.' . $node->type)->get('comment_subject_field') == 1,
     );
 
     // Used for conditional validation of author fields.
@@ -199,7 +199,7 @@ class CommentFormController extends EntityFormController {
     $element = parent::actions($form, $form_state);
     $comment = $this->getEntity($form_state);
     $node = $form_state['comment']['node'];
-    $preview_mode = variable_get('comment_preview_' . $node->type, DRUPAL_OPTIONAL);
+    $preview_mode = config('comment.settings.' . $node->type)->get('comment_preview');
 
     // No delete action on the comment form.
     unset($element['delete']);
diff --git a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
index 5dcda40..9c8e54f 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentStorageController.php
@@ -195,7 +195,7 @@ class CommentStorageController extends DatabaseStorageController {
   protected function updateNodeStatistics($nid) {
     // Allow bulk updates and inserts to temporarily disable the
     // maintenance of the {node_comment_statistics} table.
-    if (!variable_get('comment_maintain_node_statistics', TRUE)) {
+    if (!config('comment.settings')->get('comment_maintain_node_statistics')) {
       return;
     }
 
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
index e122141..7b5e94d 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentInterfaceTest.php
@@ -548,8 +548,10 @@ class CommentInterfaceTest extends CommentTestBase {
     }
 
     // Change comment settings.
-    variable_set('comment_form_location_' . $this->node->type, $info['form']);
-    variable_set('comment_anonymous_' . $this->node->type, $info['contact']);
+    config('comment.settings.' . $this->node->type)
+      ->set('comment_form_location', $info['form'])
+      ->set('comment_anonymous', $info['contact'])
+      ->save();
     if ($this->node->comment != $info['comments']) {
       $this->node->comment = $info['comments'];
       node_save($this->node);
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php
index 24d5b39..2669121 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentTestBase.php
@@ -51,16 +51,15 @@ abstract class CommentTestBase extends WebTestBase {
     $langcode = LANGUAGE_NOT_SPECIFIED;
     $edit = array();
     $edit['comment_body[' . $langcode . '][0][value]'] = $comment;
-
-    $preview_mode = variable_get('comment_preview_article', DRUPAL_OPTIONAL);
-    $subject_mode = variable_get('comment_subject_field_article', 1);
+    $preview_mode = config('comment.settings.article')->get('comment_preview');
+    $subject_mode = config('comment.settings.article')->get('comment_subject_field');
 
     // Must get the page before we test for fields.
     if ($node !== NULL) {
       $this->drupalGet('comment/reply/' . $node->nid);
     }
 
-    if ($subject_mode == TRUE) {
+    if ($subject_mode) {
       $edit['subject'] = $subject;
     }
     else {
@@ -223,7 +222,7 @@ abstract class CommentTestBase extends WebTestBase {
    *   Status message to display.
    */
   function setCommentSettings($name, $value, $message) {
-    variable_set($name . '_article', $value);
+    config('comment.settings.article')->set($name, $value)->save();
     $this->assertTrue(TRUE, t($message)); // Display status message.
   }