diff --git a/2021-Fall/assignment4/requirements.txt b/2021-Fall/assignment4/requirements.txt
index c310bc6..83dd311 100644
--- a/2021-Fall/assignment4/requirements.txt
+++ b/2021-Fall/assignment4/requirements.txt
@@ -59,7 +59,7 @@ pandocfilters==1.4.3
 parso==0.8.2
 pexpect==4.8.0
 pickleshare==0.7.5
-Pillow==8.3.2
+Pillow==9.0.0
 plotly==5.3.1
 prometheus-client==0.11.0
 prompt-toolkit==3.0.20