Backordered email notification

Hi,

It depends how you want to handle it.
For example, if you want to to send a notification to the customer when you change the status, you could just tick the "user notification" checkbox while changing the status. You could even have different statuses, for the different delays so that the message would be something like :
Your order status has been changed to {waiting for stock for 2 days} or {waiting for stock for one week}.

You could also have a mass action to notification the customers automatically when you change the status. For example:
take.ms/QoZqt
www.hikashop.com/support/documentation/167-massaction-form.html
Or maybe you want something else ?
For example, if you set the real stock of the product in the "quantity" field of the product, when it reaches 0, the customers won't be able to purchase it.
In that case, you can configure the "waitlist" feature so that the customer can subscribe to the notification email when you put back stock in the product "quantity" field.