Before upgrade ST-A/PI add on, you need to upgrade SPAM/SAINT tool. You can find guide here.
After this step you can follow steps below for upgrade ST-PI add-on.
Run report from Se38 –> RTCCTOOL for get latest version information
Check SAP Market for download ST-A/PI 01T_731.
From client 000, run transaction SAINT and load package from Front end server. Also you can copy and decompress .sar file on the OS level. You must copy files to ../trans/EPS/in folder.
Choose add on’s sp level.
You find guide for upgrade ST-PI here.