diff --git a/setup.py b/setup.py
index 1ec3a35..80df309 100644
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
 VECTORS_DEPENDENCY = "cryptography_vectors=={0}".format(about['__version__'])
 
 requirements = [
-    "idna>=2.0",
+    "idna>=2.1",
     "asn1crypto>=0.21.0",
     "packaging",
     "six>=1.4.1",