What is the best sequence to upgrade a MacPro with SoftRAID 5.8.4 from MacOS 10.15.7 to 11.3.1? First update to SoftRAID 6 and then upgrade to MacOS 11, or the other way round?
I would remove the RAID volumes, upgrade, then install the SoftRAID driver, "Allow" OWC as an identified developer, then reconnect the volume. My preference since MacOS made a mistake once of mucking with external volumes when upgrading, now my habit is remove all external disks when upgrading the OS.
Big Sur will overwrite the driver when installing, so upgrading first, while it does not hurt anything, you will have to install the driver again after the upgrade.
Thank you. In the sequence you describe would you suggest to uninstall SR 5.8.4 before upgrading the OS?
There is no need.
A limited version of SoftRAID's 6.0 driver is already bundled with intel Big Sur, it will over write it anyway.