diff --git a/src/pocketmine/inventory/FurnaceInventory.php b/src/pocketmine/inventory/FurnaceInventory.php
index 7c6219b4e..a2ee762ff 100644
--- a/src/pocketmine/inventory/FurnaceInventory.php
+++ b/src/pocketmine/inventory/FurnaceInventory.php
@@ -85,8 +85,8 @@ class FurnaceInventory extends ContainerInventory{
 		return $this->setItem(0, $item);
 	}
 
-	public function onSlotChange($index, $before){
-		parent::onSlotChange($index, $before);
+	public function onSlotChange($index, $before, $source = null){
+		parent::onSlotChange($index, $before, $source);
 		//TODO: implement Furnace scheduled update
 	}
-}
\ No newline at end of file
+}