The MailUp Extension for Magento (MailUp_MailUpSync [DISCONTINUED] - free download) allows you to leverage the powerful MailUp email messaging system from your Magento-powered eCommerce store.
Using the MailUp Extension for Magento
Magento has announced that they'd stop supporting the Magento 1.x platform, and has finally sunset the version 1 on June 2020. More info here.
Following this announcement, we have stopped supporting our integration with Magento 1 as well.