All of our software is offered in single copy or 5 Pack. A single copy covers one computer with one serial number. The 5 Pack option is one serial number with the legal right to install on up to five computers. This is a popular (and affordable) option amongst families or small businesses. The 5 Pack upgrade option is only offered to customers who had a previous 5 Pack version of the applicable software. For example: A Paperless 1 5 Pack customer can upgrade to Paperless 2 5 Pack using the 5 Pack upgrade option.