I am looking to create a flow that triggers an email that will be sent to customers when an item they ordered is back-ordered / drops to 0 inventory to all open orders with that product as well as any new orders until the product is back in stock.
The client use drop ship so when things go out of stock they manually update it in shopify and same when they get an update that its back in stock.
What is the best way to set up that flow in klaviyo?