International Civil Aviation Organization (ICAO) is an international organization for civil aviation. It is commonly known as ICAO.
It is widely believed that the change in passport numbers for Chinese citizens is required by ICAO in Document 9303.
So, I looked at the document "ICAO Machine Readable Travel Documents (MRPs) 9303 (Eighth Edition, 2021)" from the ICAO official website:
The document consists of 13 parts, with the first 4 parts being relevant to this issue. The following content is extracted from the document:
4.2 Terminology and Definitions
Control Number is the serial number assigned to the document for recording and security purposes during its production.
Document Number is the unique identification number of the document. It is recommended for the document number to be the same as the control number.
Identifier is a unique data string used as a keyword for naming a person's identity and related attributes in a biometric system. The machine-readable travel document number is an example of an identifier.
Electronic Machine Readable Passport (eMRP) is a TD3 type machine-readable travel document that meets the specifications of Part 4 of Document 9303 and has an additional built-in contactless integrated circuit capable of identifying the document holder's biometric features. It is commonly known as an "ePassport".
A.5.2.3 Numbering
It is strongly recommended to use a unique document number as the passport number.
Basic features:
• The passport number should appear on all pages of the document and on the personal data page of the document.
• The document number should be printed and/or perforated.
• The document number on the label should be a special type of digit or font and should be printed with an ink that emits fluorescence under ultraviolet light, in addition to having a visible color.
• The same technology used to load personal data during the personalization process can be used to incorporate the number of a passport made of synthetic material on the data page or machine-readable travel document card.
• For machine-readable travel document cards, the number should be displayed on both sides of the card.
Part 3: General Specifications for all Machine Readable Travel Documents is not relevant to this issue.
4.1.1.1 Visual Inspection Zone - Data Element Directory
Document Code (mandatory) indicates a machine-readable passport with the uppercase letter P. Additional uppercase letters may be added after the letter P to indicate other types of passports, such as machine-readable passports issued to diplomatic personnel, machine-readable passports issued for official travel, or passports issued for special purposes, as desired by the issuing country or authority.
Passport Number (mandatory) is a unique number assigned by the issuing country or authority to distinguish it from all other machine-readable travel documents issued by that country or authority. For more detailed information, see Part 3 of Document 9303.
Personal Number (optional) is an optional field for recording the personal identification number assigned to the holder by the issuing country or authority. For more detailed information, see Part 3 of Document 9303.
From this, it can be understood that the change in passport numbers is related to ICAO DOC 9303 (Eighth Edition, 2021).