--- a/tox.ini	Mon Oct 30 09:32:26 2017 +0100
+++ b/tox.ini	Mon Oct 30 09:37:20 2017 +0100
@@ -20,7 +20,7 @@
 [testenv:flake8]
 skip_install = true
 deps =
-  flake8 >= 3
+  flake8 >= 3.5
 whitelist_externals =
   /bin/sh
 commands = /bin/sh -c "flake8 `xargs -a {toxinidir}/flake8-ok-files.txt`"