THis was a feature previously and meant that we could see from the 'invoices' screen which invoices had been sent to the customer and which hadn't.
Also the navigation from an existing invoice ...
Please bring back the column showing 'emailed/sent' on the invoices screen. It was an easy way to see if invoices had been sent out or not without having to open each individual invoice. Also please bring back the filter of 'open and sent' on the invoices screen to search what has been sent but not paid.