diff --git a/setup.py b/setup.py
index c75df0baf..96004f08b 100644
--- a/setup.py
+++ b/setup.py
@@ -87,7 +87,7 @@ def run_tests(self):
         "six>=1.10.0,<2",
         "graphql-core>=2.1,<3",
         "graphql-relay>=0.4.5,<1",
-        "aniso8601>=3,<=6.0.*",
+        "aniso8601>=3,<=6",
     ],
     tests_require=tests_require,
     extras_require={