On February 8, 2018, U.S. Customs and Border Protection (CBP) announced updates to the Automated Commercial Environment (ACE) Stand-alone Filing for Prior Notice Data, Status Notification (PO) document in the CBP and Trade Automated Interface Requirements (CATAIR).
The updates include the additions of one reason code and several subreason codes. The codes will become available in production on February 28, 2018.
Cargo Systems Messaging Service #18-000123 announcing the changes can be found here: