Shopify is taking care of the recent PayPal SHA-256 updates
September 14, 2015
You may have received an email from PayPal saying...
PayPal service upgrades. As we have previously communicated to you, PayPal is upgrading the certificate for www.paypal.com to SHA-256. This endpoint is also used by merchants etc...
The good news is that Shopify is taking care of the changes required internally, you shouldn't need to do anything on your website provided you've got a standard Shopify/PayPal setup (all eChic clients should be fine)