diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 0e0fc08f..affc4859 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -16,15 +16,15 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {name: Linux, python: '3.8', os: ubuntu-latest, tox: py38}
-          - {name: Windows, python: '3.8', os: windows-latest, tox: py38}
-          - {name: Mac, python: '3.8', os: macos-latest, tox: py38}
+          - {name: Linux, python: '3.9', os: ubuntu-latest, tox: py39}
+          - {name: Windows, python: '3.9', os: windows-latest, tox: py39}
+          - {name: Mac, python: '3.9', os: macos-latest, tox: py39}
+          - {name: '3.8', python: '3.8', os: ubuntu-latest, tox: py38}
           - {name: '3.7', python: '3.7', os: ubuntu-latest, tox: py37}
           - {name: '3.6', python: '3.6', os: ubuntu-latest, tox: py36}
           - {name: 'PyPy', python: pypy3, os: ubuntu-latest, tox: pypy3}
-          - {name: Version Range, python: '3.8', os: ubuntu-latest, tox: 'devel'}
-          - {name: Style, python: '3.8', os: ubuntu-latest, tox: style}
-          - {name: Docs, python: '3.8', os: ubuntu-latest, tox: docs}
+          - {name: Version Range, python: '3.9', os: ubuntu-latest, tox: 'devel'}
+          - {name: Docs, python: '3.9', os: ubuntu-latest, tox: docs}
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
diff --git a/src/flask/wrappers.py b/src/flask/wrappers.py
index 43b9eeec..76a12bd0 100644
--- a/src/flask/wrappers.py
+++ b/src/flask/wrappers.py
@@ -90,7 +90,7 @@ class Request(RequestBase, JSONMixin):
             attach_enctype_error_multidict(self)
 
 
-class Response(ResponseBase, JSONMixin):
+class Response(JSONMixin, ResponseBase):
     """The response object that is used by default in Flask.  Works like the
     response object from Werkzeug but is set to have an HTML mimetype by
     default.  Quite often you don't have to create this object yourself because
diff --git a/tox.ini b/tox.ini
index cef429c9..db58200e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{38,37,36,py3}
+    py{39,38,37,36,py3}
     py38-devel
     style
     docs