In Woo v9.2 they introduced a new field labeled "GTIN, UPC, EAN or ISBN".
On their release notes they state
Classic Product Editor – Global Unique ID
Add new unique ID to the classic product form #49312
A new field called global_unique_id (currently labeled GTIN, UPC, EAN or ISBN) was added to the classic product editor. It has a behavior similar to a SKU, allowing any type of text, while asserting that the value is unique across all products. The field is available both for main products and variations.
Can you advise how this affects the ATUM stock field? Obviously, it's best to avoid repetition, so we should probably hide one of them, but are there any plans on merging them, or possibly the ability for ATUM to use the Woo one instead?
obviously there's a major difference, because the Woo one is unique whereas the ATUM one is not, so I'm not sure if this complicates things.