diff --git a/test/mailers/previews/app_mailer_preview.rb b/test/mailers/previews/app_mailer_preview.rb
index bdcc6fffc..dc6fb9760 100644
--- a/test/mailers/previews/app_mailer_preview.rb
+++ b/test/mailers/previews/app_mailer_preview.rb
@@ -53,6 +53,7 @@ class AppMailerPreview < ActionMailer::Preview
     )
   end
 
+  # <b>DEPRECATED:</b> Please use <tt>system_notification</tt> instead.
   def system_message_notification
     AppMailer.notification(
       fake_user,