Hi,
In the order listing, the popup is still present but in the order edition (in the backend), there is no more popup but you still have a "notify customer" checkbox.
We regroup the email features in the "email" button when you edit an order. In the latest HikaShop build, when you click on this button the "order status notification" email will be loaded, the same mail that you had when you changed the order status.
The difference is that the content of the email will be better. Before we load the email content before the status changed so, some data could be missing (if you have some downloadable files for example).
By moving it into the "email" button, we removed this kind of problem.
But in the order listing, you still can change the order status and get the modification popup (and the checkbox to send an email).
Regards,