Issues #123 #118 #101 - RECOMMENDED INSTALLATION
Issue #123 Support HMAC SHE-512 hash rather than md5
This change is urgent (January 2019) as the support for the legacy md5
hashing for SIM and DPM will be removed shortly. After updating, add the following attribute to your gateway:
$gateway->setSignatureKey('{long signatureKey generated in your account}')