diff --git a/HISTORY.rst b/HISTORY.rst
index bba7a2f..09d7eb1 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -3,6 +3,11 @@
 History
 =======
 
+Unreleased
+----------
+
+* Confirmed support for Django 4.0.
+
 2.1.0 (2021-03-03)
 ------------------
 
diff --git a/setup.py b/setup.py
index a3bf5fe..c9bbef7 100644
--- a/setup.py
+++ b/setup.py
@@ -27,6 +27,7 @@
         'Framework :: Django :: 3.0',
         'Framework :: Django :: 3.1',
         'Framework :: Django :: 3.2',
+        'Framework :: Django :: 4.0',
         'Intended Audience :: Developers',
         'Natural Language :: English',
         'License :: OSI Approved :: BSD License',
diff --git a/tox.ini b/tox.ini
index 2fe3f94..4bd0efa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,8 @@ envlist =
     py3{6,7,8,9}-django30
     py3{6,7,8,9}-django31
     py3{6,7,8,9}-django32
-    py3{6,7,8,9}-master
+    py3{8,9}-django40
+    py3{8,9}-main
 
 [testenv]
 basepython =
@@ -21,4 +22,5 @@ deps=
     django-30: Django>=3.0a1,<3.1
     django-31: Django>=3.1a1,<3.2
     django-32: Django>=3.2a1,<4.0
-    django-master: https://github.com/django/django/archive/master.tar.gz
+    django-40: Django>=4.0a1,<4.1
+    django-main: https://github.com/django/django/archive/main.tar.gz