diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 3a5d6b5dba..661677b51a 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -293,7 +293,7 @@ function template_preprocess_system_themes_page(&$variables) {
 
       // Make sure to provide feedback on compatibility.
       $current_theme['incompatible'] = '';
-      if (!empty($theme->incompatible_core)) {
+      if (!empty($theme->info['core_incompatible'])) {
         $current_theme['incompatible'] = t("This theme is not compatible with Drupal @core_version. Check that the .info.yml file contains a compatible 'core' or 'core_version_requirement' value.", ['@core_version' => \Drupal::VERSION]);
       }
       elseif (!empty($theme->incompatible_region)) {