diff --git a/setup.cfg b/setup.cfg
index 9b2be1b..ac3c0b8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -15,12 +15,12 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: OS Independent
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
-    Programming Language :: Python :: 2.6
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.3
     Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
     Topic :: Utilities
 
 [files]
diff --git a/setup.py b/setup.py
index f8fcdec..4e7501e 100755
--- a/setup.py
+++ b/setup.py
@@ -16,14 +16,6 @@
 
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
-
 setuptools.setup(
     setup_requires=['pbr>=1.3'],
     pbr=True)
diff --git a/test-requirements.txt b/test-requirements.txt
index e7171d9..601db9f 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,12 +2,12 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking<0.11,>=0.10.0
+flake8
 
 coverage>=3.6
 python-subunit>=0.0.18
 requests-mock>=0.6.0
-sphinx>=1.6.2
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2 # BSD
 mock>=1.2
 openstackdocstheme>=1.11.0 # Apache-2.0
 oslotest>=1.2.0  # Apache-2.0
diff --git a/tests/cmd/test_delete.py b/tests/cmd/test_delete.py
index ff94316..00df586 100644
--- a/tests/cmd/test_delete.py
+++ b/tests/cmd/test_delete.py
@@ -23,9 +23,9 @@ class TestCaseDelete(TestCase):
 
     def test_delete_without_path(self):
         required = [
-            '.*?^usage: grafana-dashboards delete \[-h\] path',
-            '.*?^grafana-dashboards delete: error: (too few arguments|the '
-            'following arguments are required: path)',
+            r'.*?^usage: grafana-dashboards delete \[-h\] path',
+            r'.*?^grafana-dashboards delete: error: (too few arguments|the '
+            r'following arguments are required: path)',
         ]
         stdout, stderr = self.shell('delete', exitcodes=[2])
         for r in required:
diff --git a/tests/cmd/test_update.py b/tests/cmd/test_update.py
index 47af29b..7cac9b1 100644
--- a/tests/cmd/test_update.py
+++ b/tests/cmd/test_update.py
@@ -23,9 +23,9 @@ class TestCaseUpdate(TestCase):
 
     def test_update_without_path(self):
         required = [
-            '.*?^usage: grafana-dashboards update \[-h\] path',
-            '.*?^grafana-dashboards update: error: (too few arguments|the '
-            'following arguments are required: path)',
+            r'.*?^usage: grafana-dashboards update \[-h\] path',
+            r'.*?^grafana-dashboards update: error: (too few arguments|the '
+            r'following arguments are required: path)',
         ]
         stdout, stderr = self.shell('update', exitcodes=[2])
         for r in required:
diff --git a/tests/cmd/test_validate.py b/tests/cmd/test_validate.py
index a76af05..7280326 100644
--- a/tests/cmd/test_validate.py
+++ b/tests/cmd/test_validate.py
@@ -102,7 +102,7 @@ class TestCaseValidate(TestCase):
 
     def _validate_invalid_file_or_directory(self, path):
         required = [
-            '%s: ERROR: \[Errno 2\] No such file or directory:' % path,
+            r'%s: ERROR: \[Errno 2\] No such file or directory:' % path,
         ]
         stdout, stderr = self.shell(
             'validate %s' % path, exitcodes=[1])
@@ -113,9 +113,9 @@ class TestCaseValidate(TestCase):
 
     def test_validate_without_path(self):
         required = [
-            '.*?^usage: grafana-dashboards validate \[-h\] path',
-            '.*?^grafana-dashboards validate: error: (too few arguments|the '
-            'following arguments are required: path)',
+            r'.*?^usage: grafana-dashboards validate \[-h\] path',
+            r'.*?^grafana-dashboards validate: error: (too few arguments|the '
+            r'following arguments are required: path)',
         ]
         stdout, stderr = self.shell('validate', exitcodes=[2])
         for r in required:
diff --git a/tests/cmd/test_version.py b/tests/cmd/test_version.py
index 918dad5..30a03c2 100644
--- a/tests/cmd/test_version.py
+++ b/tests/cmd/test_version.py
@@ -23,4 +23,4 @@ class TestCaseVersion(TestCase):
         stdout, stderr = self.shell('--version')
         self.assertThat(
             (stdout + stderr),
-            matchers.MatchesRegex('.*?^(\d+)\.(\d+)\.(\d+)'))
+            matchers.MatchesRegex(r'.*?^(\d+)\.(\d+)\.(\d+)'))
diff --git a/tox.ini b/tox.ini
index 43226b3..32b6b7a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,8 @@
 [tox]
-minversion = 1.6
-envlist = docs,pep8,py27,py35
+minversion = 3.1.1
+envlist = docs,pep8,py35,py36,py37,py38
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
 usedevelop = True
@@ -13,22 +14,18 @@ deps = -r{toxinidir}/requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'
 
 [testenv:pep8]
-basepython = python3
 commands = flake8
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 commands =
   coverage erase
   python setup.py test --coverage --coverage-package-name=grafana_dashboards --testr-args='{posargs}'
   coverage report
 
 [testenv:docs]
-basepython = python3
 commands = python setup.py build_sphinx
 
 [flake8]
@@ -36,6 +33,6 @@ commands = python setup.py build_sphinx
 # H202 skip until we actually write our own exceptions
 
 show-source = True
-ignore = E123,E125,H202
+ignore = E123,E125,H202,W503
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build