The software itself automatically checks for updates. To check manually:

On Mac, go to: /Applications/GenArtsSapphireSparks9/Check for Updates. Follow the instructions in the dialog box.
On Linux, open a shell window, and type su to become root and run the following command: /usr/discreet/sparks/sapphire_9/update-check/update-check

You can also go to http://www.genarts.com/support/downloads/sapphire/autodesk.