diff --git a/tox.ini b/tox.ini
index c32b104..ecab5cf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,7 +64,7 @@ deps =
     Pygments>=2.2.0 # BSD
     doc8>=0.8.1 # Apache-2.0
     flake8-import-order>=0.17.1 # LGPLv3
-    hacking>=4.1.0,<5.0.0 # Apache-2.0
+    hacking~=6.0.0 # Apache-2.0
     pycodestyle>=2.0.0,<3.0.0 # MIT
 commands =
     flake8 metalsmith