Creeperkat, that was added back in 2018:
https://forum.mycostpro.com/index.php?topic=224.msg600#msg600So if you have an version older than that I recommend grabbing a new download (I recommend it anyway since we released another update yesterday)
The setting to match sold items to product master by SKU is controlled from the Account Info / Settings tab.
You can also update your SKU to your active listings from the Active Listing tab.
