A new order number format
New orders will gradually move to a new number format such as PW202609193854301463: always 20 characters, starting with two letters and ending in a check digit, with easily confused letters like O and I no longer used. Existing order numbers stay valid and can still be looked up. If you use the open API, treat order numbers as opaque strings.
New order numbers look like PW202609193854301463: always 20 characters — two letters, the 8-digit order date (China time), a 9-digit number and a final check digit. The check digit lets the system catch a mistyped digit or two adjacent digits swapped straight away, and letters that are easy to confuse with digits, such as O and I, are never used. Every order number issued before the switch stays valid for good: none will be rewritten, and they can be looked up exactly as before. If you integrate through the open API, treat order_no (and parent_order_no) as an opaque string of up to 32 characters: store and compare it exactly as received, and don't validate it by prefix or fixed length — old and new formats will coexist for a long time. Your own out_order_no is unaffected, and so is looking orders up by it.