diff --git a/.circleci/config.yml b/.circleci/config.yml
index 59c930b..93080aa 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -7,85 +7,22 @@ workflows:
           matrix:
             parameters:
               python_image:
-                - "python:2.7-slim"
-                - "python:3.4-slim"
-                - "python:3.5-slim"
                 - "python:3.6-slim"
                 - "python:3.7-slim"
                 - "python:3.8-slim"
-                - "pypy:2-slim-buster"
+                - "python:3.9-slim"
                 - "pypy:3-slim-buster"
               django_version:
-                - "master"
-                - "3.0.x" # 3.x supports python 3.6 to 3.9
-                - "2.2.x" # 2.x supports python 3.4 to 3.7
-                - "2.1.x"
-                - "2.0.x"
-                - "1.11.x" # 1.11.x supports python 2.7
-                - "1.10.x"
-                - "1.9.x"
-                - "1.8.x"
+                - "2.2.x" # 2.2 supports python 3.5 to 3.9
+                - "3.2.x" # 3.0 supports python 3.6 to 3.9
+                - "main"  # 4.0 supports 3.8 to 3.9
             exclude:
-              - python_image: "python:3.8-slim"
-                django_version: "2.2.x"
-              - python_image: "python:3.8-slim"
-                django_version: "2.1.x"
-              - python_image: "python:3.8-slim"
-                django_version: "2.0.x"
-              - python_image: "python:3.8-slim"
-                django_version: "1.11.x"
-              - python_image: "python:3.8-slim"
-                django_version: "1.10.x"
-              - python_image: "python:3.8-slim"
-                django_version: "1.9.x"
-              - python_image: "python:3.8-slim"
-                django_version: "1.8.x"
-
-              - python_image: "python:3.7-slim"
-                django_version: "1.10.x"
-              - python_image: "python:3.7-slim"
-                django_version: "1.9.x"
-              - python_image: "python:3.7-slim"
-                django_version: "1.8.x"
-
-              - python_image: "python:3.6-slim"
-                django_version: "1.10.x"
               - python_image: "python:3.6-slim"
-                django_version: "1.9.x"
-              - python_image: "python:3.6-slim"
-                django_version: "1.8.x"
-
-              - python_image: "python:3.5-slim"
-                django_version: "master"
-              - python_image: "python:3.5-slim"
-                django_version: "3.0.x"
-
-              - python_image: "python:3.4-slim"
-                django_version: "master"
-              - python_image: "python:3.4-slim"
-                django_version: "3.0.x"
-
-              - python_image: "python:2.7-slim"
-                django_version: "master"
-              - python_image: "python:2.7-slim"
-                django_version: "3.0.x"
-              - python_image: "python:2.7-slim"
-                django_version: "2.2.x"
-              - python_image: "python:2.7-slim"
-                django_version: "2.1.x"
-              - python_image: "python:2.7-slim"
-                django_version: "2.0.x"
-
-              - python_image: "pypy:2-slim-buster"
-                django_version: "master"
-              - python_image: "pypy:2-slim-buster"
-                django_version: "3.0.x"
-              - python_image: "pypy:2-slim-buster"
-                django_version: "2.2.x"
-              - python_image: "pypy:2-slim-buster"
-                django_version: "2.1.x"
-              - python_image: "pypy:2-slim-buster"
-                django_version: "2.0.x"
+                django_version: "main"
+              - python_image: "python:3.7-slim"
+                django_version: "main"
+              - python_image: "pypy:3-slim-buster"  # on 3.7 as of 2021-07-26
+                django_version: "main"
 
 jobs:
   test:
@@ -111,7 +48,6 @@ jobs:
           condition:
             not:
               or:
-                - equal: [ "pypy:2-slim-buster", << parameters.python_image >> ]
                 - equal: [ "pypy:3-slim-buster", << parameters.python_image >> ]
           steps:
             - run:
@@ -123,7 +59,6 @@ jobs:
       - when:
           condition:
             or:
-              - equal: [ "pypy:2-slim-buster", << parameters.python_image >> ]
               - equal: [ "pypy:3-slim-buster", << parameters.python_image >> ]
           steps:
             - run:
diff --git a/.gitignore b/.gitignore
index f5b55d2..90f56c0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 *.db
 *.sw[po]
 .cache
+.coverage
 .tox
 dist
 build
diff --git a/csp/tests/test_context_processors.py b/csp/tests/test_context_processors.py
index 6c4f062..df980a4 100644
--- a/csp/tests/test_context_processors.py
+++ b/csp/tests/test_context_processors.py
@@ -3,9 +3,11 @@
 
 from csp.middleware import CSPMiddleware
 from csp.context_processors import nonce
+from csp.tests.utils import response
+
 
 rf = RequestFactory()
-mw = CSPMiddleware()
+mw = CSPMiddleware(response())
 
 
 def test_nonce_context_processor():
diff --git a/csp/tests/test_contrib.py b/csp/tests/test_contrib.py
index 33998ab..98ccded 100644
--- a/csp/tests/test_contrib.py
+++ b/csp/tests/test_contrib.py
@@ -3,10 +3,11 @@
 from django.test.utils import override_settings
 
 from csp.contrib.rate_limiting import RateLimitedCSPMiddleware
+from csp.tests.utils import response
 
 
 HEADER = 'Content-Security-Policy'
-mw = RateLimitedCSPMiddleware()
+mw = RateLimitedCSPMiddleware(response())
 rf = RequestFactory()
 
 
diff --git a/csp/tests/test_decorators.py b/csp/tests/test_decorators.py
index 6f2716e..a4bd733 100644
--- a/csp/tests/test_decorators.py
+++ b/csp/tests/test_decorators.py
@@ -4,10 +4,11 @@
 
 from csp.decorators import csp, csp_replace, csp_update, csp_exempt
 from csp.middleware import CSPMiddleware
+from csp.tests.utils import response
 
 
 REQUEST = RequestFactory().get('/')
-mw = CSPMiddleware()
+mw = CSPMiddleware(response())
 
 
 def test_csp_exempt():
diff --git a/csp/tests/test_middleware.py b/csp/tests/test_middleware.py
index f9413ce..ce06b24 100644
--- a/csp/tests/test_middleware.py
+++ b/csp/tests/test_middleware.py
@@ -7,10 +7,11 @@
 from django.test.utils import override_settings
 
 from csp.middleware import CSPMiddleware
+from csp.tests.utils import response
 
 
 HEADER = 'Content-Security-Policy'
-mw = CSPMiddleware()
+mw = CSPMiddleware(response())
 rf = RequestFactory()
 
 
diff --git a/csp/tests/utils.py b/csp/tests/utils.py
index 7d7814f..d3f9a83 100644
--- a/csp/tests/utils.py
+++ b/csp/tests/utils.py
@@ -1,11 +1,22 @@
+from django.http import HttpResponse
 from django.template import engines, Template, Context
 from django.test import RequestFactory
 
 from csp.middleware import CSPMiddleware
 
 
+def response(*args, headers=None, **kwargs):
+    def get_response(req):
+        response = HttpResponse(*args, **kwargs)
+        if headers:
+            for k, v in headers.items():
+                response.headers[k] = v
+        return response
+    return get_response
+
+
 JINJA_ENV = engines['jinja2']
-mw = CSPMiddleware()
+mw = CSPMiddleware(response())
 rf = RequestFactory()
 
 
diff --git a/setup.cfg b/setup.cfg
index 260edd9..b92ce01 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,3 @@
-[wheel]
-universal = 1
-
 [tool:pytest]
 addopts = -vs --tb=short --pep8 --flakes
 
diff --git a/setup.py b/setup.py
index a371bce..b945bdc 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@ def read(*parts):
 
 
 install_requires = [
-    'Django>=1.8',
+    'Django>=2.2',
 ]
 
 jinja2_requires = [
@@ -32,6 +32,7 @@ def read(*parts):
 
 test_requires = [
     'pytest<4.0',
+    'pytest-cov',
     'pytest-django',
     'pytest-flakes==1.0.1',
     'pytest-pep8==1.0.6',
@@ -78,11 +79,7 @@ def read(*parts):
         'Intended Audience :: Developers',
         'Topic :: Software Development :: Libraries :: Python Modules',
         'Programming Language :: Python',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.4',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
diff --git a/tox.ini b/tox.ini
index 3618e29..65c4dbd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,16 +1,8 @@
 [tox]
 envlist =
-    {3.6,3.7,3.8,3.9,pypy3}-master,
-    {3.6,3.7,3.8,3.9,pypy3}-3.2.x,
-    {3.6,3.7,3.8,3.9,pypy3}-3.1.x,
-    {3.6,3.7,3.8,3.9,pypy3}-3.0.x,
-    {3.5,3.6,3,7,pypy3}-2.2.x,
-    {2.7,3.4,3.5,3.6,pypy,pypy3}-2.1.x,
-    {3.4,3.5,3.6,pypy3}-2.0.x,
-    {2.7,3.4,3.5,3.6,pypy,pypy3}-1.11.x,
-    {2.7,3.4,3.5,3.6,pypy}-1.10.x,
-    {2.7,3.4,3.5,3.6,pypy}-1.9.x,
-    {2.7,3.4,3.5,3.6,pypy}-1.8.x
+    {3.6,3.7,3.8,3.9,pypy3}-main
+    {3.6,3.7,3.8,3.9,pypy3}-3.0.x
+    {3.6,3,7,3.8,3.9,pypy3}-2.2.x
 
 [testenv]
 setenv =
@@ -18,30 +10,16 @@ setenv =
     PYTHONDONTWRITEBYTECODE=1
 commands =
     pip install --upgrade pip setuptools wheel
-    pip install pytest-cov
-    pip install -e .
     pip install -e .[tests]
-    py.test --cov={toxinidir}/csp  {toxinidir}/csp
+    pytest --cov={toxinidir}/csp  {toxinidir}/csp
 basepython =
-    2.7: python2.7
-    3.4: python3.4
-    3.5: python3.5
     3.6: python3.6
     3.7: python3.7
     3.8: python3.8
     3.9: python3.9
-    pypy: pypy
     pypy3: pypy3
 deps=
     pytest
-    1.8: Django>=1.8,<1.9
-    1.9: Django>=1.9,<1.10
-    1.10: Django>=1.10,<1.11
-    1.11: Django>=1.11,<1.12
-    2.0: Django>=2.0,<2.1
-    2.1: Django>=2.1,<2.2
-    2.2: Django>=2.2,<2.3
-    3.0: Django>=3.0,<3.1
-    3.1: Django>=3.1,<3.2
-    3.2: Django>=3.2,<4.0
-    master: https://github.com/django/django/archive/master.tar.gz
+    2.2.x: Django>=2.2,<2.3
+    3.2.x: Django>=3.2,<3.3
+    main: https://github.com/django/django/archive/main.tar.gz