diff --git c/core/modules/system/lib/Drupal/system/Controller/ThemeListingController.php w/core/modules/system/lib/Drupal/system/Controller/ThemeListingController.php
index 7b637ec..a470332 100644
--- c/core/modules/system/lib/Drupal/system/Controller/ThemeListingController.php
+++ w/core/modules/system/lib/Drupal/system/Controller/ThemeListingController.php
@@ -93,7 +93,7 @@ public function listingPage() {
         // Ensure this theme is compatible with this version of core.
         // Require the 'content' region to make sure the main page
         // content has a common place in all themes.
-        $theme->incompatible_core = !isset($theme->info['core']) || ($theme->info['core'] != DRUPAL_CORE_COMPATIBILITY) || !isset($theme->info['regions']['content']);
+        $theme->incompatible_core = !isset($theme->info['core']) || ($theme->info['core'] != \DRUPAL::CORE_COMPATIBILITY) || !isset($theme->info['regions']['content']);
         $theme->incompatible_php = version_compare(phpversion(), $theme->info['php']) < 0;
         // Confirmed that the base theme is available.
         $theme->incompatible_base = isset($theme->info['base theme']) && !isset($themes[$theme->info['base theme']]);