diff --git a/docs/settings.rst b/docs/settings.rst
index ae3fb2df..dd6a3ea3 100644
--- a/docs/settings.rst
+++ b/docs/settings.rst
@@ -81,6 +81,10 @@ These changes are visible throughout django-helpdesk
 - **HELPDESK_EMAIL_FALLBACK_LOCALE** Fallback locale for templated emails when queue locale not found
 
   **Default:** ``HELPDESK_EMAIL_FALLBACK_LOCALE= "en"``
+  
+- **QUEUE_EMAIL_BOX_UPDATE_ONLY** Only process mail with a valid tracking ID; all other mail will be ignored instead of creating a new ticket.
+
+  **Default:** ``False``
 
 
 Options shown on public pages
diff --git a/helpdesk/settings.py b/helpdesk/settings.py
index 6fd8e460..18d63a18 100644
--- a/helpdesk/settings.py
+++ b/helpdesk/settings.py
@@ -133,6 +133,8 @@ QUEUE_EMAIL_BOX_SSL = getattr(settings, 'QUEUE_EMAIL_BOX_SSL', None)
 QUEUE_EMAIL_BOX_HOST = getattr(settings, 'QUEUE_EMAIL_BOX_HOST', None)
 QUEUE_EMAIL_BOX_USER = getattr(settings, 'QUEUE_EMAIL_BOX_USER', None)
 QUEUE_EMAIL_BOX_PASSWORD = getattr(settings, 'QUEUE_EMAIL_BOX_PASSWORD', None)
+
+# only process emails with a valid tracking ID? (throws away all other mail)
 QUEUE_EMAIL_BOX_UPDATE_ONLY = getattr(settings, 'QUEUE_EMAIL_BOX_UPDATE_ONLY', False)
 
 # only allow users to access queues that they are members of?