Avoid PayPal Service Disruption – Magento Merchants Must Upgrade or Apply a PayPal Patch by June 30, 2017
If your store uses PayPal, you must upgrade or apply a patch by June 30, 2017 to avoid potential service disruption. Why? For increased security, merchants will only be able to use HTTPS when posting messages back to PayPal via their Instant Payment Notification (IPN) service. In the past, PayPal has allowed the use of HTTP for these postbacks.
To comply, Magento merchants using PayPal must upgrade to:
All Magento 2.1.x versions already support this change, so no update is required.