require idna 2.0 or better because it's better
diff --git a/setup.py b/setup.py
index e0b5738..77f6dcd 100644
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,7 @@
 VECTORS_DEPENDENCY = "cryptography_vectors=={0}".format(about['__version__'])
 
 requirements = [
-    "idna",
+    "idna>=2.0",
     "pyasn1",
     "six>=1.4.1",
     "setuptools"