diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -51,7 +51,7 @@ requirements = [
     "WebHelpers2 >= 2.0, < 2.1",
     "FormEncode >= 1.3.1, < 1.4",
     "SQLAlchemy >= 1.1, < 1.4",
-    "Mako >= 0.9.0, < 1.1",
+    "Mako >= 0.9.1, < 1.1",
     "Pygments >= 2.2.0, < 2.5",
     "Whoosh >= 2.5.0, < 2.8",
     "celery >= 3.1, < 4.0", # TODO: celery 4 doesn't work