diff --git a/requirements.txt b/requirements.txt
index 095bc8e..cad0b6f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ coverage==4.5.1
 enum34==1.1.6
 flake8==3.5.0
 funcsigs==1.0.2
-idna==2.6
+idna==2.9
 isort==4.3.4
 mccabe==0.6.1
 more-itertools==4.1.0