Recentrly I had been a SAP PI 7.1 system to SAP PO 7.5 and some scnearios I had troubles with the acknowldege reponse from other SAP systems.
The problem is with a SOAP XI receiver communitation channel when the message is sended to sap system receiver, I don’t know because the receiver system send to PO a aknowledge with empty content (XML), and this raise a exception in PO.
To fix that I need to add this parameters into adapter module > Tab Module > Module Configuration
Module Key Parameter Name Parameter Value soap XMBWS.GenerateSysAck true soap MBWS.NoSOAPIgnoreStatusCode true soap GenerateSysAck true soap ignoreDuplicate true
Maybe the parameters sounds to do other actions, but when you set the value ‘true‘the akcnowldege is ignored in PO and the process complete succesfully.