diff --git a/requirements.txt b/requirements.txt
index 35fa4a2..2e5e635 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,7 @@ chardet==3.0.4
 fusepy==2.0.4
 idna==2.6
 inflection==0.3.1
+iso8601==0.1.12
 Jinja2==2.9.4
 MarkupSafe==1.0
 peewee==2.8.5