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, search for GenArts Sapphire AVX -> Check for Sapphire AVX Updates.
On Mac, go to: /Applications/GenArtsSapphireAVX/Check for Sapphire AVX Updates.

Notifications are also made available through standard GenArts communications, i.e., newsletters or other email communication.