dcramer/django-paypal — pull request #30 by mij (2013-08-18 14:44:56+00:00)
Title: add IPN signal for failed payments in subscription

Add a signal for PayPal notifying via IPN that a user's subscription failed a payment. This notification is crucial to respond to, because the event normally results in PayPal shortly discontinuing the subscription and the bussiness losing the customer.