Comment by zinekeller

> With a limit of 10 million different serial numbers, I wonder how China does it.

The author has issued a correction, it's 100 million numbers per service indicator. But even then, it's probably not enough.

The boring answer is that your shipping options are either get untracked postal service (which the S10 standard does not apply) or use a private courier (which also does not use the S10 standard).

If you insist, you got two options for UPU-based postal tracking: normal e-commerce parcel aka H-codes, practically 2,300,000,000 trackable packages per year [1]. EMS is the other route, and there are another 2,300,000,000 trackable packages per year [2]. However, in my experience tracked postal delivery is only used in certain countries where it is more advantageous than private delivery (like until very recently in the US, for complicated reasons [3]), while other destinations has a more-than-willing private delivery partner (that is not the Big Three [4]) or even set up the delivery systems themselves.

1: 23 service indicators: HA-HW, HX-HZ are reserved for multilateral/bilateral use only

2: another 23 service indicators: EA-EW, EX-EZ are reserved for multilateral/bilateral use only

3: https://www.thewirechina.com/2020/11/22/delivering-chinas-ma... https://www.ft.com/content/a1233f3e-d21a-11e8-a9f2-7574db66b...

4: DHL, FedEx, and UPS