ISO IEC 10646-2020 amd1-2023 PDF

Full title and description

ISO/IEC 10646:2020/Amd 1:2023 — Information technology — Universal coded character set (UCS) — Amendment 1: CJK Unified Ideographs Extension H, Vithkuqi, Old Uyghur, Cypro‑Minoan, and other characters. This amendment updates the ISO/IEC 10646:2020 repertoire and supporting artefacts to add multiple new blocks and characters (including historic and minority scripts and the large CJK Extension H block), and to align the standard’s code charts and normative references with the corresponding Unicode deliverables.

Abstract

This amendment to ISO/IEC 10646:2020 extends the Universal Coded Character Set by adding new scripts and thousands of code points (notably CJK Unified Ideographs Extension H and several historic/script blocks such as Vithkuqi, Old Uyghur and Cypro‑Minoan), updates code charts and source-reference files, and brings the ISO/IEC repertoire into alignment with the character assignments published in Unicode Version 15.0. Implementers of character-encoding infrastructure (fonts, input methods, text processors and data registries) should consult the amended charts and metadata for correct encoding and rendering.

General information

• Status: Published.
• Publication date: 17 July 2023.
• Publisher: Joint ISO/IEC publication (ISO in partnership with IEC / JTC 1).
• ICS / categories: 35.040.10 — Coding of character sets.
• Edition / version: Edition 6 (Amendment 1 to ISO/IEC 10646:2020).
• Number of pages: 447 (amendment document page count).

Scope

This amendment applies to ISO/IEC 10646:2020 and extends the encoded repertoire by adding new blocks and individual characters across multiple planes. It incorporates updated code charts, source-reference files, name‑alias and variation-sequence metadata, and updates normative references to align with the Unicode data and annexes used for the corresponding Unicode release. The amendment is intended to formalize the additions so that implementers relying on ISO/IEC 10646 have a stable international-standard definition for the newly encoded characters.

Key topics and requirements

• Addition of new blocks and code points to the UCS repertoire — notably CJK Unified Ideographs Extension H and several historic/script blocks (Vithkuqi, Old Uyghur, Cypro‑Minoan, among others).
• Alignment of ISO/IEC 10646 code charts, name aliases, and metadata with the Unicode release corresponding to these additions (Unicode Version 15.0).
• Updated normative references and source-reference files so implementers can map between ISO/IEC 10646 and Unicode data files for interoperability.
• Implications for implementers: font vendors, text-processing libraries, input-method developers, and database systems must update tables, fonts and rendering rules to support the new code points and sequences. (Guidance and code charts are provided in the amendment.)
• Large-scale CJK additions (Extension H) significantly expand CJK coverage and require attention for collation, rendering and CJK-specific font glyph coverage.

Typical use and users

Primary users are software and platform vendors, operating system and font developers, database and search-system engineers, standards bodies and national registries, academic linguists, digital archivists and any organisation that encodes, stores or renders multilingual text. Governments and institutions preserving historic texts or using minority-script data will particularly benefit from the historic/script additions.

Related standards

ISO/IEC 10646:2020 (base standard) — this document is Amendment 1 to that edition. The amendment is aligned with The Unicode Standard (Version 15.0) and its associated Unicode Character Database and annexes; implementers should consult both ISO/IEC 10646 and the corresponding Unicode data files for full technical details and mapping guidance. Other related deliverables include subsequent ISO/IEC amendments or corrigenda and Unicode Technical Reports relevant to character properties and normalization.

Keywords

UCS, Unicode, character set, ISO/IEC 10646, Amendment 1, CJK Extension H, Vithkuqi, Old Uyghur, Cypro‑Minoan, code charts, character repertoire, encoding, Unicode 15.0

FAQ

Q: What is this standard?

A: It is Amendment 1 (2023) to ISO/IEC 10646:2020 — the international standard that defines the Universal Coded Character Set (UCS), providing an updated and extended repertoire of encoded characters.

Q: What does it cover?

A: The amendment adds new characters and blocks (notably CJK Unified Ideographs Extension H and several historic/minority scripts including Vithkuqi, Old Uyghur and Cypro‑Minoan), updates the standard’s code charts and metadata, and aligns the ISO repertoire with the corresponding Unicode release.

Q: Who typically uses it?

A: Software vendors, OS and font developers, input-method and rendering-engine implementers, database and search-system engineers, standards bodies, linguists and archivists — anyone responsible for accurate encoding, storage, interchange and rendering of text.

Q: Is it current or superseded?

A: The amendment was published on 17 July 2023 and is current as an amendment to ISO/IEC 10646:2020. Future amendments or a later edition of ISO/IEC 10646 may further revise the repertoire; users should monitor ISO/IEC JTC 1/SC 2 and Unicode Consortium publications for subsequent changes.

Q: Is it part of a series?

A: Yes — it is part of the ISO/IEC 10646 family (the Universal Coded Character Set) and is maintained in coordination with the Unicode Standard; the ISO standard is kept up to date through amendments/corrigenda that reflect accepted Unicode repertoire extensions.

Q: What are the key keywords?

A: UCS, Unicode, code charts, CJK Extension H, Vithkuqi, Old Uyghur, Cypro‑Minoan, character repertoire, ISO/IEC 10646, encoding.