Multiple Follow Up Emails - Order and Delivery Status

one thing we've noticed is that an order can be shipped with the tracking number but customers don't always track the package until it seems that the package is late, in which case most often the package is somewhere on the premises but anyone at the home/biz might have moved the package, customers will say "hey, i didn't get it", when really it was delivered like four days before

it would be most cool if an additional follow-up email could go out once the package is "delivered", at their doorstep, this would help alert customers to look for the package when it is most likely to be found, someone hasn't yet gotten to it and misplaced it

this could involve i guess some sort of cron query of ups/fedex/usps/etc of orders shipped but not yet delivered, and then fire out the "delivered" follow-up

thanks

USPS, Fedex and UPS all have ways to send emails on updates on their sites. You can click it on when you generate labels from fedex or ups, not sure how to tie this in with opencart, but the systems do exist. Since I don't use their shipping modules but ship by weight, not sure if this is something that could be added to the modules?