Bernd was correct in his use of naming, CA must take the lead as the vendor to show understanding of the IBM landscape that they support!
The IBM System i is IBM's previous generation of midrange computer systems for IBM i users, and was subsequently replaced by the IBM Power Systems in April 2008
But System i references the hardware and what this question is about the operating system so please use the correct names so in this case " current supported operating system version of Power system for Plex 7.x is IBM i 7.2"
Please see IBM i (Power Systems software) and vote Stop Referring to System i