diff --git a/charms_openstack/charm/core.py b/charms_openstack/charm/core.py
index b50304e..c1d0f0d 100644
--- a/charms_openstack/charm/core.py
+++ b/charms_openstack/charm/core.py
@@ -334,7 +334,6 @@ class BaseOpenStackCharmMeta(type):
         :param mro: tuple of base classes.
         :param members: dictionary of name to class attribute (f, p, a, etc.)
         """
-        global _releases
         # Do not attempt to calculate the release for an abstract class
         if members.get('abstract_class', False):
             return
diff --git a/test-requirements.txt b/test-requirements.txt
index 9e00ae1..35e5ec8 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,8 +2,8 @@ simplejson
 requests
 httpretty
 pep8
-flake8>=2.2.4
+flake8>=7.1.1
 stestr
-paramiko<2.0
+paramiko
 charms.reactive
 coverage>=3.6