Have you realized you cannot send that attachment as an attachment in the email to the customer? Also, I have yet to find a way to see the attachment from the customer's view of the invoice. So... there is no connection to any supporting document for the customer's invoice. This is evidently not a bug (as many other things I've experienced with this new update) but intentionally removed as an option. I've found a few comments but I would imagine there are a lot more that are experiencing the pain of this issue.