diff --git a/requirements-app.txt b/requirements-app.txt
index 3d86f371d..15eec61a7 100644
--- a/requirements-app.txt
+++ b/requirements-app.txt
@@ -12,7 +12,7 @@ Flask==1.1.2
 click-datetime==0.2
 eventlet==0.29.1
 gunicorn==20.0.4
-iso8601==0.1.12
+iso8601==0.1.13
 itsdangerous==1.1.0
 jsonschema==3.2.0
 marshmallow-sqlalchemy==0.23.1