SoftRAID 4 is not officially supported and does not qualify for upgrade discounts. You can still purchase SoftRAID Lite and ask our customer service team for a SoftRAID 4 license, if you are running 10.3, 10.4, or 10.5. SoftRAID 5 supports 10.6, 10.7, 10.8, 10.9, 10.10, and 10.11.
For all later versions of MacOS, use SoftRAID 7.