Shipping status:

0 Pending 

100 Processing / Picking

200 Shipped

201 Partially Shipped

200 Digital and Gift Certificate Products result in Order Status Shipped

200 Shipped, with RMA Issued or Returned items that should not affect the status

201 Partially Shipped 

300 Cancelled

400 Backordered

500 RMA Issued

600 Returned

Some stuff from the LSK:

| 0-100: Ignore items going from the pending state to picking state - Module_Notify_OrderShipment_Insert will handle this
| 100-200: Ignore items going from the picking state to shipped state - Module_Notify_OrderShipment_StatusChange will handle this
| 200-500: Ignore items going from the shipped state to RMA issued state - Module_Notify_OrderReturn_Insert will handle this
| 500-600: Ignore items going from the RMA issued state to Returned state - Module_Notify_OrderReturn_StatusChange will handle this