Assume that you are using EDIFACT interchanges to send messages to your partner in Microsoft BizTalk Server 2010 or 2013. You leave the UNB9 (Acknowledgment request) field in UNB Segment Definition Page (EDI Properties) of the Parties node in BizTalk Server Administrator Console as the default value.
Note The default value for the UNB9 (Acknowledgment request) field is 0 - ACK not required.
In this situation, you may receive an error message from your partner that says the EDIFACT message is invalid.
Cumulative update information
This issue was first fixed in the following cumulative update of BizTalk Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For information about the service packs and cumulative update list for BizTalk Server, see KB 2555976: Service pack and cumulative update list for BizTalk Server.
For more information about BizTalk Server hotfixes, see KB 2003907: Information about BizTalk hotfixes and Service Pack support.