I have posted a mail item for some time. Why does the mail tracing system always show that the mail item has departed only?

Once a mail item is sent overseas, all the handling records subsequent to its departure will be provided and updated by the destination postal administration concerned on a voluntary basis. Given the fact that certain postal administrations will not share with us their mail processing data, tracking information of the mail item up to departure from Hong Kong can only be shown in our mail tracing system. If this is the case, you may trace the item at the mail tracking website of the destinations via our Mail Tracking webpage. You may also contact our Mail Tracing Office where necessary.