What should a store say when an item is out of stock but may return soon?

A local commerce question about stockout messages, uncertain restock dates, and substitute options.

A temporary stockout message has to be honest without sounding useless. If the supplier has not confirmed the date, “back soon” can create more frustration than clarity. I would rather see the item name, current status, best estimate if available, substitute option, and whether the customer can be notified. How specific should a small store be when the return date is uncertain? Is a careful range better than no date, or does that still create a promise customers may rely on?