diff --git a/postorius/mailman-web/settings.py b/postorius/mailman-web/settings.py
index 57e64e3..ab10f2b 100644
--- a/postorius/mailman-web/settings.py
+++ b/postorius/mailman-web/settings.py
@@ -143,6 +143,11 @@ DATABASES = {
     'default': dj_database_url.config(conn_max_age=600)
 }
 
+# Avoid Django 3.2+ warning
+# https://github.com/maxking/docker-mailman/issues/595
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'
+
+
 # If you're behind a proxy, use the X-Forwarded-Host header
 # See https://docs.djangoproject.com/en/1.8/ref/settings/#use-x-forwarded-host
 USE_X_FORWARDED_HOST = True
diff --git a/web/mailman-web/settings.py b/web/mailman-web/settings.py
index 7ab51ed..c19a827 100644
--- a/web/mailman-web/settings.py
+++ b/web/mailman-web/settings.py
@@ -156,6 +156,11 @@ DATABASES = {
     'default': dj_database_url.config(conn_max_age=600)
 }
 
+# Avoid Django 3.2+ warning
+# https://github.com/maxking/docker-mailman/issues/595
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'
+
+
 # If you're behind a proxy, use the X-Forwarded-Host header
 # See https://docs.djangoproject.com/en/1.8/ref/settings/#use-x-forwarded-host
 USE_X_FORWARDED_HOST = True