diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 052b315..a1511f6 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -7,8 +7,7 @@
  * The theme system allows for nearly all output of the Drupal system to be
  * customized by user themes.
  */
-
-use Drupal\Component\Utility\Json;
+use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\String;
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Component\Utility\Xss;
diff --git a/core/modules/system/src/Tests/Theme/FunctionsTest.php b/core/modules/system/src/Tests/Theme/FunctionsTest.php
index 0a20300..a905a5c 100644
--- a/core/modules/system/src/Tests/Theme/FunctionsTest.php
+++ b/core/modules/system/src/Tests/Theme/FunctionsTest.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\system\Tests\Theme;
 
-use Drupal\Component\Utility\Json;
+use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\String;
 use Drupal\Core\Session\UserSession;
 use Drupal\simpletest\WebTestBase;