This extension adds a new tab to the order info view, which lists all other orders of the customer.

If the customer is registered, it gets all other orders by searching through all orders with the customer_id. Guests will be looked up by firstname + lastname.

You can select the other orders and then update all selected by using the form under the table. The update happens via AJAX and won't reload the page.

This extension doesn't add any file or does any change in your database. It's a single install.xml file with my changes.

There is a free version of my extension which shows all other orders of the customer, but doesn't have the mass update feature: