Retail version of the software is a full version of the software which includes the installation disc(s), Certificate of Authenticity (if manufacturer provides), and the product keycode/serial number (if necessary). OEM software does not come in a retail box, doesn't include any printed manuals, and it is not eligible for a free technical support from the manufacturer. You can always find the “Help” files in the member’s area. OEM software is only available in "full version" editions, meaning there are no OEM upgrade products. OEM software can be upgraded to future versions of the software by purchasing a compatible upgrade product.