shopUpz app provides bi-directional quantity updates so you will not oversell. For example when a new order comes from Etsy the app will update Shopify quantity based on the listing SKU vice versa, if the order comes from Shopify shopUpz will update your Etsy quantity automatically.
Sold out listing status is the only exception. Here is what you need to do: When a sold out listing is back in stock please update Etsy listing to active with the right quantity and shopUpz app will automatically update your Shopify listing based on the same SKU.
For any other Etsy listing status you can decide if you want to update the quantity on Shopify or on Etsy and we will update the other store accordingly.
ShopUpz correctly updates the item quantity on Etsy when it increases or decreases on Shopify --- including for SOLD OUT items but the ShopUpz incorrectly changes the Shopify item quantity to 0 for items with SOLD OUT status. Why??? ShopUpz should leave the Shopify item quantity alone. This is a bug and should be fixed.