diff --git a/assignment1/requirements.txt b/assignment1/requirements.txt
old mode 100755
new mode 100644
index 4d9577c..59add16
--- a/assignment1/requirements.txt
+++ b/assignment1/requirements.txt
@@ -32,7 +32,7 @@ mistune==0.8.4
 nbconvert==5.4.1
 nbdime==1.0.5
 nbformat==4.4.0
-notebook==5.7.8
+notebook==6.4.12
 numpy==1.16.2
 pandocfilters==1.4.2
 parso==0.3.4