With PeepSo Actvitity Bump Admin can set the activities to be bumped on the top of the Activity stream page When a community member comment 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 on the top when a community member post a reply to any of the comment (for related activity).