diff --git a/requirements.txt b/requirements.txt
index f6f5354ff2..37b1855d85 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,7 +16,7 @@ flask-mail==0.9.1
 flask-sslify==0.1.5
 Flask-Limiter==0.9.3
 passlib==1.6.2
-aniso8601==1.1.0
+aniso8601==4.1.0
 blinker==1.3
 psycopg2==2.7.3.2
 python-dateutil==2.4.2