CNV-17038: Default storage class - auto update

Author: apinnick

virt/virtual_machines/advanced_vm_management/virt-automatic-bootsource-updates.adoc

@@ -10,7 +10,9 @@ You can use boot sources that are _system-defined_ and included with {VirtProduc
 
 [IMPORTANT]
 ====
-As of version 4.10, {VirtProductName} automatically imports and updates boot sources, unless you manually opt out. If you upgrade to version 4.10, you must manually enable automatic imports and updates for boot sources from version 4.9 or earlier.
+As of version 4.10, {VirtProductName} automatically imports and updates boot sources, unless you manually opt out or do not set a default storage class.
+
+If you upgrade to version 4.10, you must manually enable automatic imports and updates for boot sources from version 4.9 or earlier.
 ====
 
 include::modules/virt-enabling-bootsource-update.adoc[leveloffset=+1]