From https://docs.djangoproject.com/en/3.2/releases/3.2/#customizing-type-of-auto-created-primary-keys:

When defining a model, if no field in a model is defined with primary_key=True an implicit primary key is added. The type of this implicit primary key can now be controlled via the DEFAULT_AUTO_FIELD setting and AppConfig.default_auto_field attribute. No more needing to override primary keys in all models.

Maintaining the historical behavior, the default value for DEFAULT_AUTO_FIELD is AutoField.

tox.ini

@@ -8,6 +8,7 @@ envlist=
     py{35,36,37}-django22
     py{36,37,38}-django30
     py{36,37,38}-django31
+    py{36,37,38}-django32
 
 [testenv]
 passenv=EMAIL_IMAP_SERVER EMAIL_ACCOUNT EMAIL_PASSWORD EMAIL_SMTP_SERVER
@@ -18,6 +19,7 @@ deps=
     django22: django==2.0.*
     django30: django==3.0.*
     django31: django==3.1.*
+    django32: django==3.2.*
     -r{toxinidir}/test_requirements.txt
 sitepackages=False
 commands=