Every online shop needs to send e-mails and so the Aimeos e-commerce framework does. They are still the best option to confirm the order and tell customers about changes in the delivery and payment status. Nevertheless, even nowadays, creating appealing e-mails for different devices is hard stuff! Software seem to be from year 2000 when comparing support for HTML5 and CSS in e-mail clients.
Most of the time, support is limited for security reasons which is a good thing because compared to web sites you have to visit actively, everyone can send you e-mails. But often, simple features aren’t implemented since more than ten years or are buggy and therefore unusable. Outlook falls into the later category and it seems that Microsoft wants to punish us forever!