diff --git a/setup.py b/setup.py
index a1b8c5da..62485148 100755
--- a/setup.py
+++ b/setup.py
@@ -24,6 +24,7 @@ install_requires = [
     "jsondiff==1.1.1",
     "aws-xray-sdk!=0.96,>=0.93",
     "responses>=0.9.0",
+    "idna<2.8,>=2.5",
 ]
 
 extras_require = {