Merchant Security Updates: Learn how security upgrades may affect your integration at the 2016-2017 Merchant Security Roadmap Microsite
Payments Standard Updates: Beginning March 29th 2017, PayPal will offer a few enhancements that may require integration changes. Read more here: Payments Standard Upgrade FAQ
Not sure exactly what you mean, but it sounds like the redirect back to your thank you page, after the customer completes payment doesnt happen? Am I right?