Have used the new super rate update tool from V34 (2025) under Employees/Update Super. This seems to update the Active Employees and the payroll Super item to the new rate.
But, have found that the default rate that can be set in preferences is not updated and needs to be manually changed (Edit/Preferences/Payroll & Employees/Company/Defaults/Super).
This default allows any New Employee to automatically have the provided Super Item and Super Rate applied