PayPal has issued a security update to their PayFlow Pro payment gateway and requesting all clients using the gateway update to the new API’s by September 1st. These important updates have been included in Pinnacle Cart versions 3.6.3 and 3.6.4. To continue processing payments, please make plans to update your Pinnacle Cart application as soon as possible. Please contact customer support if you have any questions.
More information about this update can be found at https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/gateway_update