diff --git a/tiegcm/requirements.txt b/tiegcm/requirements.txt
index b738cfc..1dfb9c2 100644
--- a/tiegcm/requirements.txt
+++ b/tiegcm/requirements.txt
@@ -1,4 +1,4 @@
-certifi==2016.9.26
+certifi==2022.12.7
 cftime==1.0.3.4
 netCDF4==1.5.2
 numpy==1.17.3