diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 7d52064..76317ed 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "pypy-3.7", "pypy-3.8"]
 
     steps:
     - uses: actions/checkout@v1
diff --git a/.gitignore b/.gitignore
index dd56309..7190a6b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,4 @@ tests/db.sqlite*
 /tests/local.db
 /.venv
 .vscode/settings.json
+pyrightconfig.json
diff --git a/advanced_filters/forms.py b/advanced_filters/forms.py
index e14794f..0ffe761 100644
--- a/advanced_filters/forms.py
+++ b/advanced_filters/forms.py
@@ -14,7 +14,6 @@
 from django.db.models import Q
 from django.db.models.fields import DateField
 from django.forms.formsets import formset_factory, BaseFormSet
-from django.utils.functional import cached_property
 from functools import reduce
 from django.utils.text import capfirst
 from django.utils.translation import gettext_lazy as _
@@ -200,14 +199,6 @@ def get_form_kwargs(self, index):
         kwargs['model_fields'] = self.model_fields
         return kwargs
 
-    @cached_property
-    def forms(self):
-        # override the original property to include `model_fields` argument
-        forms = [self._construct_form(i, model_fields=self.model_fields)
-                 for i in range(self.total_form_count())]
-        forms.append(self.empty_form)  # add initial empty form
-        return forms
-
 
 AFQFormSet = formset_factory(
     AdvancedFilterQueryForm, formset=AdvancedFilterFormSet,
diff --git a/advanced_filters/urls.py b/advanced_filters/urls.py
index a8fd76e..4fc8320 100644
--- a/advanced_filters/urls.py
+++ b/advanced_filters/urls.py
@@ -1,14 +1,14 @@
-from django.conf.urls import url
+from django.urls import path
 
 from advanced_filters.views import GetFieldChoices
 
 urlpatterns = [
-    url(r'^field_choices/(?P<model>.+)/(?P<field_name>.+)/?',
+    path('field_choices/<model>/<field_name>/',
         GetFieldChoices.as_view(),
         name='afilters_get_field_choices'),
 
     # only to allow building dynamically
-    url(r'^field_choices/$',
+    path('field_choices/',
         GetFieldChoices.as_view(),
         name='afilters_get_field_choices'),
 ]
diff --git a/setup.py b/setup.py
index fd1272f..61cbf74 100644
--- a/setup.py
+++ b/setup.py
@@ -78,14 +78,15 @@ def get_full_description():
         'Operating System :: OS Independent',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3 :: Only',
         'Framework :: Django',
         'Framework :: Django :: 2.2',
         'Framework :: Django :: 3.1',
+        'Framework :: Django :: 4.0',
         'Topic :: Internet :: WWW/HTTP',
         'Topic :: Internet :: WWW/HTTP :: Dynamic Content',
     ],
diff --git a/tests/test_project/urls.py b/tests/test_project/urls.py
index f3c5556..e249e36 100644
--- a/tests/test_project/urls.py
+++ b/tests/test_project/urls.py
@@ -1,7 +1,7 @@
-from django.conf.urls import include, url
+from django.urls import include, path
 from django.contrib import admin
 
 urlpatterns = [
-    url(r'^admin/', admin.site.urls),
-    url(r'^advanced_filters/', include('advanced_filters.urls'))
+    path('admin/', admin.site.urls),
+    path('advanced_filters/', include('advanced_filters.urls'))
 ]
diff --git a/tox.ini b/tox.ini
index 82a1810..25371e0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,21 +1,20 @@
 [tox]
 envlist =
-    py{36,37,38,39,py3}-django{22,31}
-    ; py{36,37,38,39}-django{22,31,32}
+    py{37,py37}-django{22,32}
+    py{38,py38,39}-django{22,32,40}
+    py310-django{32,40}
     report
-    clean
 
 [pycodestyle]
 max-line-length = 120
 
 [testenv]
 usedevelop = true
-passenv = TRAVIS TRAVIS_*
 deps =
     -rtest-reqs.txt
     django22: Django>=2.2,<3.0
-    django31: Django>=3.1,<3.2
-    ; django32: Django>=3.2,<3.3
+    django32: Django>=3.2,<3.3
+    django40: Django>=4.0,<4.1
 
 depends =
     !report: clean
@@ -27,32 +26,20 @@ commands =
     pytest --cov-append .
     pycodestyle --exclude=urls.py,migrations,.ropeproject -v advanced_filters
 
-[travis]
-python =
-  3.6: py36
-  3.7: py37
-  3.9: py39
-  pypy3: pypy3
-
-[travis:env]
-DJANGO =
-  2.2: django22
-  3.1: django31
-  ; 3.2: django32
-
 [gh-actions]
 python =
-  3.6: py36
   3.7: py37
   3.8: py38
   3.9: py39
-  pypy3: pypy3
+  3.10: py310
+  pypy-3.7: pypy37
+  pypy-3.8: pypy38
 
 [gh-actions:env]
 DJANGO =
   2.2: django22
-  3.1: django31
-  ; 3.2: django32
+  3.2: django32
+  4.0: django40
 
 [testenv:report]
 deps = coverage