Shippers may choose to send a parcel by rapid speed post or affordable registered mail. For low valued items, shippers usually prefer the unregistered service.
Thus, a registered mail is trackable and unregistered surface mail doesn't have full tracking information.
In fact, surface parcels will be bagged into a large pack and the carrier will throw them into the dispatching center for departure, that's all the info you will have. No additional info will be updated after departure.