diff --git a/spatial_theme.theme b/spatial_theme.theme
index 7e0bfc1..8acfd4a 100644
--- a/spatial_theme.theme
+++ b/spatial_theme.theme
@@ -1,4 +1,7 @@
 <?php
+use Drupal\file\Entity\File;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\File\FileSystemInterface;
 /**
  * @file
  * Spartial-theme.
@@ -29,7 +32,7 @@ function spatial_theme_preprocess_page(array &$variables) {
   $welcome_article_id = theme_get_setting('article_block');
   $fid = theme_get_setting('background_file');
   if (!empty($fid)) {
-    $file = \Drupal\file\Entity\File::load($fid[0]);
+    $file = File::load($fid[0]);
     $file_url = $file->getFileUri();
     $variables['page']['background_url'] = file_create_url($file_url);
   }
@@ -58,7 +61,7 @@ function spatial_theme_preprocess_page(array &$variables) {
 
 }
 
-function spatial_theme_form_system_theme_settings_alter(&$form, \Drupal\Core\Form\FormStateInterface &$form_state, $form_id = NULL) {
+function spatial_theme_form_system_theme_settings_alter(&$form, FormStateInterface &$form_state, $form_id = NULL) {
   // Work-around for a core bug affecting admin themes. See issue #943212.
   if (isset($form_id)) {
     return;
@@ -112,7 +115,7 @@ function spatial_theme_form_system_theme_settings_alter(&$form, \Drupal\Core\For
     '#default_value' => theme_get_setting('article_block'),
   );
   $default_file_dir = 'public://template/background-image';
-  $folder = file_prepare_directory($default_file_dir, FILE_CREATE_DIRECTORY);
+  $folder = \Drupal::service('file_system')->prepareDirectory($default_file_dir, FileSystemInterface::CREATE_DIRECTORY);
 
   if ($folder) {
     $background_file = theme_get_setting('background_file');
@@ -139,12 +142,12 @@ function spatial_theme_form_system_theme_settings_alter(&$form, \Drupal\Core\For
 function spatial_theme_save_background_file($image, $theme) {
   $fid = theme_get_setting($image, $theme);
   if ($fid > 0) {
-    $file = file_load($fid);
+    $file = \Drupal::service('entity_type.manager')->getStorage('file')->load($fid);
     if (is_object($file) && $file->status == 0) {
       $file->status = FILE_STATUS_PERMANENT;
       file_save($file);
       file_usage_add($file, $theme, 'theme', 1);
-      drupal_set_message($image . ' saved permanently.', 'status');
+      \Drupal::messenger()->addStatus($image . ' saved permanently.');
     }
   }
 }
@@ -171,7 +174,7 @@ function spatial_render_menu($menu_name) {
   $tree = $menu_tree->transform($tree, $manipulators);
   // Finally, build a renderable array from the transformed tree.
   $menu = $menu_tree->build($tree);
-  return array('#markup' => drupal_render($menu));
+  return array('#markup' => \Drupal::service('renderer')->render($menu));
 }
 
 /**
@@ -216,7 +219,7 @@ function spatial_theme_preprocess_views_view(&$variables) {
 /**
  * Implements hook_form_alter.
  */
-function spatial_theme_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
+function spatial_theme_form_alter(&$form, FormStateInterface $form_state, $form_id) {
   if ($form_id == 'contact_message_feedback_form') {
     $form['subject']['widget'][0]['value']['#placeholder'] = t('Enter your subject');
     $form['subject']['widget'][0]['value']['#title_display'] = 'hidden';