"ShadowProtect SPX is the official name for ShadowProtect 6. ShadowProtect 5, will be continue being supported and there will even be a maintenance release, however no new features will be introduced for the older version of the product." - StorageCraft Support Forum (http://www.storagecraft.com/support/forum/shadowprotect-spx-vs-storagecraft-shadowprotect-desktop-5) If you are on version 5 with maintenance, you can upgrade for free. If you are not on maintenance, the upgrade price from version 5 is $49.98. Otherwise, it's $100 to buy the new SPX.