What is IPNV2?
Instant Payment Notification (IPN) is PayPal's interface for handling real-time purchase confirmation and server-to-server communications. IPN delivers immediate notification and confirmation of PayPal payments you receive and provides status and additional data on pending, cancelled, or failed transactions. IPN can be used to manage and customize a variety of PayPal-enabled APIs and communications, including:

Customize your website's response to customer purchases in real-time

Track customers via IPN "pass through" variables

Deliver access keys for software downloads and other digital goods

Automate your fulfillment operations

Track affiliate sales and commissions

Store transaction information in your own database

Source: PayPal
Important
This has not gone live yet but if you would like to test the demo please contact me at shinkaiho@hotmail.com.