Postmark PHP integration for Opencart 2.1.0.2 (without Composer)

Postmark PHP integration for Opencart 2.1.0.2

This is a integration of Postmark Official PHP Library for OpenCart 2.1.0.2, that can be use without Composer

How to install

1. Open your config.php and add define('POSTMARK_SERVER_API', your-postmark-server-api);
2. Upload vendors folder to OpenCart main directory (nothing will be replaced).
3. Make a backup of your mail.php file inside system/library/ directory.
4. Upload the modified mail.php file to system/library/

Works only on PHP 5.5 or higher.