The only compatiblity issue between SalesCQ and Inventory V8.1C involves the addition of an inventory item. If you add an inventory item in SalesCQ, the index that allows lookup by item description is not updated. The DIC in Inventory will notice the problem and happily rebuild the index . No data will be lost (although the DIC error might be a little disconcerting). If you advise people not to add inventory items from SalesCQ, you won't notice this at all.