Its important to keep on top of your compilation warnings. If you don’t, you end up getting flooded and increase the chances of missing an important warning and eventually receiving a phone call from Microsoft or suffering from a production outage.
Feature class does not have runtime support for this type.
Check the Feature Class property for the element that generates the warning. If the property is set, it’s likely that the runtime doesn’t support features for this object type yet so remove the property if you can.
For example, the PlanningPriority field on the PurchPurchaseOrderLineV2Entity has the Feature Class property set to ReqPriorityBasedPlanningFeature, but as of v10.0.18 the runtime doesn’t support features for Data Entities. Extending this data entity will generate the warning.