use apps.is_installed

two_factor/plugins/phonenumber/apps.py

@@ -1,4 +1,4 @@
-from django.apps import AppConfig
+from django.apps import AppConfig, apps
 from django.conf import settings
 from django.test.signals import setting_changed
 
@@ -20,8 +20,7 @@ def update_registered_methods(sender, setting, value, **kwargs):
     # This allows for dynamic registration, typically when testing.
     from .method import PhoneCallMethod, SMSMethod
 
-    installed_apps = getattr(settings, 'INSTALLED_APPS') or []
-    phone_number_app_installed = 'two_factor.plugins.phonenumber' in installed_apps
+    phone_number_app_installed = apps.is_installed('two_factor.plugins.phonenumber')
 
     if phone_number_app_installed and getattr(settings, 'TWO_FACTOR_CALL_GATEWAY', None):
         registry.register(PhoneCallMethod())