From Intuit QuickBooks Support:
“The ability to send invoices containing an IPN payment link and send payments with the Pay Vendor tool will be shut off on May 31, 2016. Your customers will still be able to pay invoices through your Pay Link until June 30, 2016. You can also download any IPN payments you receive and review past transactions until June 30, 2016.”
Intuit has replaced the Intuit Payment Network with a new eInvoicing capability for you to bill your customers. Your customers will still be able to pay you online and enjoy an updated payment experience.
Whether you are an IPN Website User, QuickBooks for Mac, or QuickBooks for Windows user; go here to see the options available to you.