Smarty is an old template engine that some scripts use as their template system
Saddly theres no official plugin for jalali date support
Recently i had to work with this engine for a client so after some research i came across this issue.
Clone the repo and copy everything from plugin
to your /path/to/smarty/plugins
{$row['id']|jdate_format:"%Y/%m/%d"}
This project was not created by me how ever theres no repo or even download links for it.
basically its an abandoned project