The software automatically checks for updated versions.  If you would like to check manually:

On Windows 7, go to: Start > All Programs > GenArts Sapphire AVX > Check for Sapphire AVX Updates.
On Windows 8 & 10, search for GenArts Sapphire AVX > Check for Sapphire AVX Updates.
On Mac, go to: /Applications/GenArtsSapphireAVX/Check for Sapphire AVX Updates.

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