diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index 7091202..2de41bb 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -17,6 +17,6 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install tox tox-gh-actions
+          python -m pip install tox tox-gh-actions
       - name: Test with tox
         run: tox
diff --git a/README.md b/README.md
index ef6ded7..8cb14f8 100644
--- a/README.md
+++ b/README.md
@@ -95,7 +95,7 @@ class SiteConfiguration(SingletonModel):
 Installation
 ------------
 
-This application requires Django 2.2, 3.1, or 3.2.
+This application requires Django 2.2, 3.2, or 4.0.
 
 * Install the package using `pip install django-solo`
 * Add ``solo`` or ``solo.apps.SoloAppConfig`` to your ``INSTALLED_APPS`` setting.
diff --git a/setup.py b/setup.py
index 3068d60..b12b452 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
-from setuptools import setup, find_packages
 import os
-import solo
+import re
 
+from setuptools import setup, find_packages
 
 README = os.path.join(os.path.dirname(__file__), 'README.md')
 
@@ -12,11 +12,24 @@
 except Exception:
     long_description = ''
 
+
+def get_version(package):
+    """
+    Return package version as listed in `__version__` in `__init__.py`.
+    """
+    with open(os.path.join(package, '__init__.py')) as file:
+        init_py = file.read()
+    return re.search("__version__ = ['\"]([^'\"]+)['\"]", init_py).group(1)
+
+
+version = get_version('solo')
+
 setup(
     name='django-solo',
-    version=solo.__version__,
-    description=solo.__doc__,
+    version=version,
+    description='Django Solo helps working with singletons',
     python_requires='>=3.6',
+    install_requires=['django>=2.2'],
     packages=find_packages(),
     url='https://github.com/lazybird/django-solo/',
     author='lazybird',
@@ -27,8 +40,8 @@
     license='Creative Commons Attribution 3.0 Unported',
     classifiers=[
         'Framework :: Django :: 2.2',
-        'Framework :: Django :: 3.1',
         'Framework :: Django :: 3.2',
+        'Framework :: Django :: 4.0',
         'Intended Audience :: Developers',
         'Operating System :: OS Independent',
         'Programming Language :: Python',
diff --git a/solo/__init__.py b/solo/__init__.py
index 4c4c5b3..870356c 100644
--- a/solo/__init__.py
+++ b/solo/__init__.py
@@ -4,7 +4,6 @@
 
 
 __version__ = '1.2.0'
-__doc__ = 'Django Solo helps working with singletons'
 
 if django.VERSION < (3, 2):
     default_app_config = 'solo.apps.SoloAppConfig'
diff --git a/solo/admin.py b/solo/admin.py
index accaeb2..a811537 100644
--- a/solo/admin.py
+++ b/solo/admin.py
@@ -1,16 +1,12 @@
 from django.urls import re_path
 from django.contrib import admin
 from django.http import HttpResponseRedirect
+from django.utils.encoding import force_str
+from django.utils.translation import gettext as _
 
 from solo.models import DEFAULT_SINGLETON_INSTANCE_ID
 from solo import settings as solo_settings
 
-try:
-    from django.utils.encoding import force_unicode
-except ImportError:
-    from django.utils.encoding import force_text as force_unicode
-from django.utils.translation import ugettext as _
-
 
 class SingletonModelAdmin(admin.ModelAdmin):
     object_history_template = "admin/solo/object_history.html"
@@ -56,7 +52,7 @@ def get_urls(self):
 
     def response_change(self, request, obj):
         msg = _('%(obj)s was changed successfully.') % {
-            'obj': force_unicode(obj)}
+            'obj': force_str(obj)}
         if '_continue' in request.POST:
             self.message_user(request, msg + ' ' +
                               _('You may edit it again below.'))
diff --git a/solo/templatetags/solo_tags.py b/solo/templatetags/solo_tags.py
index 530ec0e..de0cdfe 100644
--- a/solo/templatetags/solo_tags.py
+++ b/solo/templatetags/solo_tags.py
@@ -1,5 +1,5 @@
 from django import template
-from django.utils.translation import ugettext as _
+from django.utils.translation import gettext as _
 
 from solo import settings as solo_settings
 
diff --git a/tox.ini b/tox.ini
index 70fc906..e70b509 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,20 +1,21 @@
 # Configure which test environments are run for each Github Actions Python version.
 [gh-actions]
 python =
-    3.6: py36
-    3.7: py37
-    3.8: py38
-    3.9: py39
-    3.10: py310
+    3.6: py36-django{22,32}
+    3.7: py37-django{22,32}
+    3.8: py38-django{22,32,40}
+    3.9: py39-django{22,32,40}
+    3.10: py310-django{22,32,40}
 
 [tox]
 envlist =
-    py{36,37,38,39,310}-django{22,31,32}
+    py{36,37}-django{22,32}
+    py{38,39,310}-django{22,32,40}
 
 [testenv]
 deps =
-    django22: Django>=2.2,<2.3
-    django31: Django>=3.1,<3.2
-    django32: Django>=3.2,<3.3
+    django22: Django>=2.2,<3.0
+    django32: Django>=3.2,<4.0
+    django40: Django>=4.0,<4.1
 commands =
     {envpython} {toxinidir}/manage.py test solo --settings=solo.tests.settings