diff --git a/old_code/python_kalman_filter/requirements.txt b/old_code/python_kalman_filter/requirements.txt
index a7b75f9..b893b82 100644
--- a/old_code/python_kalman_filter/requirements.txt
+++ b/old_code/python_kalman_filter/requirements.txt
@@ -1,4 +1,4 @@
-certifi==2020.6.20
+certifi==2023.7.22
 cycler==0.10.0
 kiwisolver==1.3.1
 matplotlib==3.3.2