diff --git a/tox.ini b/tox.ini
index bc4e10dc..a117f91a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,7 +18,7 @@ commands = stestr run {posargs}
 
 [testenv:pep8]
 deps=
-    hacking>=4.1.0,<5.0.0 # Apache-2.0
+    hacking~=6.0.0 # Apache-2.0
     flake8-import-order>=0.17.1 # LGPLv3
     pycodestyle>=2.0.0,<3.0.0 # MIT
 commands = flake8 {posargs}