The installation of the PTF RO87785 requires an IPL to put in but in case of needed backout does it require an IPL?
Release: SMDI3900200-12.5-Disk-Backup and Restore-for z/OS
This new SVC module change is link with new hooks code activation so you would not have to return to the previous version.
Now if really something would happen, you will have to redo IPL or use the SETPROG command to replace the LPA module dynamically.
Normally you should be able to replace the module dynamically without any IPL by using such command: SETPROG LPA,ADD,MODNAME=ADSMVS60,DSNAME=SYS1.USER.LPALIB,SVCNUMDEC=244