1. In a computer controlled scanning and printing system, a method of providing an updated version of a printed document comprising: storing data for generating an original version of a printed document including: a two dimensional barcode having: data identifying said original version of said document; and a portion of said data for generating said original version of said document; enabling the updating of said stored data wherein a later version of said printed document may be generated including a new barcode for identifying and generating said later version; scanning the barcode of a version of said document to determine if the scanned barcode identifies the later version of the document, and generating and printing the later version of said document if the scanned barcode does not identify the later version.