diff --git a/requirements.txt b/requirements.txt
index e56352c..22f2f98 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ idna
 jmespath
 pandoc
 pip
-pytz
+pytz==2018.4
 pkginfo
 ply
 python-dateutil