Cannot install/upgrade Catalina with 5.8.3.
I tried to upgrade to Catalina having a Thunderbay 4 with SoftRaid XT and 5.8.3 version.
Upgrading straight away did not work due to installer not able to work over the current RAID volume with the message "You cannot install over this volume as it belongs to a SoftRaid volume".
I did the upgrade the same way that was advised in previous versions; backup with Carbon Copy, install over the backup volume in an external disk and, then, restore with Carbon Copy over the initial RAID volume.
The problems starts when Carbon Copy needs an AFPS volume to restore from a Catalina installation. Now I am completely stuck.
How can Catalina be installed in a RAID 5 with SoftRaid XT?.
With High Sierra, you could clone to a SoftRAID and let it be a boot volume.
Neither Mojave nor Catalina allow a SoftRAID volume to be a startup volume.
So it cannot be done. This is a result of the extra security Apple is adding to starting up, they locked down everything. I do not think this will ever be available again.