I understand that I need to login to the sub account, -->settings-->PSNetwork Acct Mgmnt-->Account info-->Upgrade Account.... When i follow this trail, the option to "Upgrade Account" doesn't show up! I bought the PS4 in Dec and believe I have the most recent software (but not 100%)
The only reason I'm trying to do this is because this user can't sign into EA games (Star Wars BattleFront & PVZ2 specifically)