diff --git a/phpBB/includes/cron/cron_task_base.php b/phpBB/includes/cron/cron_task_base.php
index f66894e7b2..3561f4e14f 100644
--- a/phpBB/includes/cron/cron_task_base.php
+++ b/phpBB/includes/cron/cron_task_base.php
@@ -27,7 +27,7 @@ if (!defined('IN_PHPBB'))
 *
 * @package phpBB3
 */
-abstract class cron_task_base
+abstract class cron_task_base implements cron_task
 {
 	/**
 	* Runs this cron task.