Symptom
Old tasks are still showing up on To-Do List evern though "Drop supplemental tasks from the To-Do list after 60 days, even if they are not done" is enabled in the TO-do serttings.
Resolution
The setting "Drop supplemental tasks from the To-Do list after 60 days, even if they are not done" is only responsible for removing the "supplemental tasks". "supplemental tasks" are the todo tasks created through todo admin UI. But the Calibration, Performance, Learning, etc.. todo tasks are NOT supplemental tasks, these are realted to module. So turning on the configuration: "Drop supplemental tasks from the To-Do list after 60 days, even if they are not done" won't help at all.
Further more, in todo admin tool, there is no configuration to help stop displaying the calibration todo since any overdue task is always supposed to display. It is reasonable and as per the system design tasks are shown in the To-do list since these sessions are still in progress status.
Keywords
Old To-Do tasks Calibration Supplemental , KBA , LOD-SF-PLT , Platform Foundational Capabilities , How To