diff --git a/python_kalman_filter/requirements.txt b/python_kalman_filter/requirements.txt
index a7b75f9..8f7a5d0 100644
--- a/python_kalman_filter/requirements.txt
+++ b/python_kalman_filter/requirements.txt
@@ -4,7 +4,7 @@ kiwisolver==1.3.1
 matplotlib==3.3.2
 numpy==1.19.4
 pandas==1.1.4
-Pillow==8.0.1
+Pillow==9.0.0
 pyparsing==2.4.7
 python-dateutil==2.8.1
 pytz==2020.4