8.6 libvirt guest XML block device (errata, not a bug)

Home KVM -
8.5 uses libvirt 6.00
8.6 uses libvirt 8.00

If you are having issues starting your guests after the upgrade and you use block devices… you may wish to check XML config changes

My guests’ Block devices no longer worked with disk type=file and source file ="[enter dev path here]"
Must now use disk type=block and source dev="[enter dev path here]"

I believe this is just version errata and not a bug.
Just wanted to share the experience.