Version 4.3.6

applications/core/modules/front/promote/promote.php

@@ -318,7 +318,7 @@ class _promote extends \IPS\Dispatcher\Controller
 		
 		try
 		{
-			if( !$class OR !class_exists( $class ) )
+			if( !$class OR !class_exists( $class ) OR !is_subclass_of( $class, 'IPS\Content' ) )
 			{
 				throw new \InvalidArgumentException;
 			}