Changing the content of an "update" e-mail

Dear Opencart members,

Can someone help me with an issue I'm facing? If I change the status of an order, for example to "shipped", and I notify the customer, the customer gets an e-mail with this update. In this update, the first line contains the Order ID. I wish to remove this line, since I think it's none of my customers business how many products I've sold

What file do I need to edit to remove this line? Thanks in advance, it is much appreciated!

The "Order ID" does not inform anyone as to how many products have been sold, just an implied indication of how many orders have been placed.

However, the customer may have placed more than one order with your website. Subsequently, when you update an order to "Shipped" (or any other status), the customer needs to know which order has been updated.

It should be noted, that the customer has already received the order id in the email they would have received from their original purchase.