Update virtual-machine-scale-sets-upgrade-scale-set.md

mimckitt · web-flow · commit 73ee8c56dc7f · 2020-03-17T08:43:14.000-07:00
diff --git a/articles/virtual-machine-scale-sets/virtual-machine-scale-sets-upgrade-scale-set.md b/articles/virtual-machine-scale-sets/virtual-machine-scale-sets-upgrade-scale-set.md
@@ -338,6 +338,7 @@ Some properties can only be set when you create the scale set. These properties
 - Availability Zones
 - Image reference publisher
 - Image reference offer
+- Image reference sku
 - Managed OS disk storage account type
 
 ### Properties that can only be changed based on the current value
