Now, the online store sellers, like on AliExpress, ship the items via the Ordinary Small Packet Plus.
This service offered by CHINA POST is an Airmail, reasonable-priced and faster service. The tracking is possible with the 11-digit tracking numbers without any letters until the item leaves China.
Also, some new services are added such as the YANWEN EXPRESS provided by Beijing YANWEN Logistics Co., Ltd. as a partner of AliExpress. The tracking no.s are YC123456789YW formatted.