...To run the SDK, your system will need to meet the minimum requirements, including having PHP >= 5.5. We highly recommend having it compiled with the cURL extension and cURL 7.16.2+ compiled with a TLS backend (e.g., NSS or OpenSSL). To run the SDK, your system will need to meet the minimum requirements, including having PHP >= 5.5. We highly recommend having it compiled with the cURL extension and cURL 7.16.2+ compiled with a TLS backend (e.g., NSS or OpenSSL).