diff --git a/includes/Defines.php b/includes/Defines.php
index 1bcb058314d..2ddd05352c3 100644
--- a/includes/Defines.php
+++ b/includes/Defines.php
@@ -213,6 +213,7 @@ require_once __DIR__.'/normal/UtfNormalDefines.php';
 define( 'MW_SUPPORTS_EDITFILTERMERGED', 1 );
 define( 'MW_SUPPORTS_PARSERFIRSTCALLINIT', 1 );
 define( 'MW_SUPPORTS_LOCALISATIONCACHE', 1 );
+define( 'MW_SUPPORTS_CONTENTHANDLER', 1 );
 /**@}*/
 
 /** Support for $wgResourceModules */