When downloading the PDF documents (invoices, offers, reminders), the file is named in a structure specified by projo. Currently when I've deciphered it correctly:

(YEAR) - (MONTH) - (INVOICE NUMBER) - (ADVANCE STATEMENT) - (INDEX)

Here it would be nice if you could configure the export yourself something (similar to the number ranges)

For example, in

(YY) - (MM) - (TT) Invoice (INVOICE NO) - AZ (ADVANCE STATEMENT) - (INDEX) - (PROJECT NAME)