diff --git a/Charpter 21/TodoList/requirements.txt b/Charpter 21/TodoList/requirements.txt
old mode 100755
new mode 100644
index 184b58f..23ec638
--- a/Charpter 21/TodoList/requirements.txt	
+++ b/Charpter 21/TodoList/requirements.txt	
@@ -11,7 +11,7 @@ cloudpickle==0.5.3
 constantly==15.1.0
 cryptography==2.3.1
 cssselect==1.0.3
-dask==0.18.2
+dask==2021.10.0
 decorator==4.3.0
 fake-useragent==0.1.10
 Flask==1.0.2