With PeepSo Actvitity Bump Admin can set the activities to be bumped on the top of the Activity stream page When a community member comments on the activity.
to enable the setting, Navigate to PeepSo Settings >> configuration >> PeepSo Activity bump
If the above setting is enabled from the backend, older activities will be bumped to the top when a community member posts a reply to any of the comments (for related activity).