We need to run a custom function when the stock level of an item changes - specifically when it goes out of stock or comes into stock, but it wouldn't matter if it was triggered by any change.

At the moment, it's triggered when any field in the item is edited, but it seems that doesn't include the Stock on Hand field - indeed, if you change it to when a particular field is edited, that isn't one of the options offered.  It also seems to be the case that no actual edit has to take place - merely clicking on Edit, then Save, is enough to trigger the function.

So - is there any way for it to be triggered when the Stock on Hand is updated?

Thanks