Does upgrading to SoftRAID 8 require me to reformat my disks, or erase my volume?

Upgrading to SoftRAID 8 will not affect your disks. SoftRAID will not need to erase your volume or update your disks. The upgrade process only replaces certain files on the startup volume. Drivers in macOS always reside in the system, not on the SoftRAID disks, so they are not impacted by a driver update.