For SystemPac users, SystemPac follow-on service (SFS) comes free as an option as part of the SystemPac fee offering. You can order a maximum of three SFSs with maximum intervals of 90 days apart. SFSs contain PTFs fixing PEs and HIPERs. They are built according to the copy of the SMP/E consolidated software inventory (CSI) of your system. Thus, these critical services are tailored to fit your environment.