ISO 20271-1:2026

• Abstract:

  This document provides an overview of the ISO 20271 series. The following are covered in this document: the scope and structure of the ISO 20271 series; description of textual document files within the scope of the ISO 20271 series; a summary of the content of each part in the ISO 20271 series; guidelines for the extension of other types of document formats.

• Status: Published
• Publication Date: 19-Oct-2026
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• ICS: 37.080 - Document imaging applications
• Technical Committee: ISO/TC 171/SC 2 - Document file formats, EDMS systems and authenticity of information
• Drafting Committee: ISO/TC 171/SC 2/WG 10 - File format guidelines
• Current Stage: 6060 - International Standard published
• Start Date: 20-Oct-2026
• Completion Date: 20-Oct-2026

ISO 20271-1:2026 is an International Organization for Standardization (ISO) overview of the ISO 20271 series for document management. It covers a reference model for the long-term preservation of textual documents and explains how the series is organized, what kinds of textual document files are in scope, and how the other parts fit together. It is written for people who analyze, develop, manage, or preserve document formats and need a shared technical framework.

What does ISO 20271-1:2026 specify?

ISO 20271-1:2026 specifies the overview and structure of the ISO 20271 series, not a standalone test method or product requirement set. It also describes the kinds of textual document files the series addresses and gives guidance for extending the model to other document types.

Part	What it covers
ISO 20271-1	Overview, scope, structure, and extension guidance
ISO 20271-2	Reference model for analyzing textual document formats and preserving their layers
ISO 20271-3	Taxonomy of characteristic information and reference markup for properties in the model

Clause 1 sets the scope around the series as a whole. Clause 2 has no normative references. Clause 3 defines the key terms used in the overview, and Clauses 4 to 7 explain the series, its applicable document types, possible extension to other types, and its audience.

What are the key requirements of ISO 20271-1:2026?

ISO 20271-1:2026 is mainly a framing document. Its key value is that it tells readers how to use the rest of the ISO 20271 series and how to think about textual document preservation in practice.

The series is a structured reference model

Clause 4 presents ISO 20271 as a reference model and framework for technical review of textual documents. In practice, this means the series is meant to help people identify which document layers and metadata matter for long-term preservation and to judge whether a format is suitable for that purpose.

ISO 20271-2 gives the core analytical model

Clause 4.2 says ISO 20271-2 provides the model for technical analysis of textual documents, including layers and preservation recommendations for each layer. For users, this is the part that supports format review, preservation planning, and decisions about what must be retained.

ISO 20271-3 adds taxonomy and reference markup

Clause 4.3 says ISO 20271-3 defines a taxonomy for characteristic information and provides a reference markup schema and example instances. That matters because it gives a way to classify document properties and express them in a structured, machine-interpretable form.

The model is intended for iterative use

The introduction says the series is meant to be applied as a coherent and iterative process. In practice, that means users can analyze a format, classify its properties, assess preservation risk, and refine the assessment as formats and technologies change.

The scope covers several textual document families

Clause 5 lists the document families in scope: simple text-based formats, text formats with presentation features, formats with external dependencies, plain-text formats with lightweight markup, packaged document formats, and semi-structured textual data formats. This helps readers decide whether their file type belongs in the series before applying the model.

Extension to other document types is possible

Clause 6 says the model may be extended to other document types by adding layers and properties suited to their technical characteristics. It also notes that the series can be used alongside archival reference models, which is important when a team needs both technical analysis and archival practice.

The series supports preservation work, not just description

The introduction says the series supports analysis, identification and classification of document properties, definition of preservation requirements, and assessment of long-term preservation risks. That makes it useful for planning, format governance, and technical decision-making.

What terms does ISO 20271-1:2026 define?

• Packaged format - A format that combines text, images, tables, and related objects in one container file so they can be stored, transferred, and preserved together.
• Semi-structured data - Data that has some organization but does not follow a rigid, fully predefined structure.
• Textual document - A document where text-based content is the main carrier of meaning, even if it also includes images, audio, or video.
• Reference model - The conceptual structure the series uses to analyze textual documents and their layers.
• Reference markup - An illustrative way to represent the defined properties in structured, machine-interpretable form.
• Long-term preservation - The preservation context addressed by the series, focused on accessibility and usability over time.

Who uses ISO 20271-1:2026?

ISO 20271-1:2026 is aimed at organizations and practitioners involved in the creation, management, and preservation of textual documents. The document names archivists and curators, digital preservation specialists, document format developers, and researchers and standards developers.

In practice, these users apply the series when analyzing document formats, identifying and classifying document properties, defining preservation requirements, and assessing long-term preservation risks. It is also relevant to system architects and other stakeholders who need to understand how a format behaves over time.

Which standards are used with ISO 20271-1:2026?

Clause 2 has no normative references. The bibliography names related standards and technical documents that provide context for the kinds of formats and technologies discussed in the series.

• ISO 19005 (all parts) - Electronic document file format for long-term preservation.
• ISO 32000 (all parts) - Portable Document Format (PDF).
• ISO/IEC 26300 (all parts) - OpenDocument Format for Office Applications.
• ISO/IEC 29500 (all parts) - Office Open XML file formats.
• ISO/IEC/TS 38505-3:2021 - Data quality guidelines for analytics and machine learning data classification.
• W3C text layout notes and MathML 3.0 - Background for layout and mathematical markup used in textual documents.

What does the ISO 20271-1:2026 document contain?

The document contains a foreword, an introduction, seven clauses, and a bibliography. Figure 1 shows the structure of the ISO 20271 series and how Parts 1, 2, and 3 relate to one another.

Clause 4 gives the most useful technical content: a summary of the series, the role of the reference model, and the relationship between layers, taxonomy, and markup. Clause 5 lists the kinds of textual document files covered, while Clause 6 explains how the model can be extended to other document types. Clause 7 identifies the intended audience.

International
Standard
ISO 20271-1
First edition
Document management —
2026-10
Reference model for long-
term preservation of textual
documents —
Part 1:
Overview
Gestion des documents — Modèle de référence pour une
conservation à long terme des documents textuels —
Partie 1: Vue d'ensemble
Reference number
© ISO 2026
All rights reserved.
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued by ISO,
an ISO member body, or an authorized third-party distributor.
Except as required for implementation or expressly permitted by a separate licence, no part of this ISO publication may be
reproduced, distributed, modified, used, or made available in any form or by any means – electronic or mechanical, including
photocopying, scanning, recording, or posting on internal or external digital platforms.
Any use beyond the scope of the granted rights is prohibited and may result in legal action.
ISO copyright office
CP 401 • CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Summary of the ISO 20271 series . 2
4.1 General .2
4.2 Summary of ISO 20271-2: Fundamental .3
4.3 Summary of the ISO 20271-3: Taxonomy and markup .3
4.4 Preservation assessment methodology .3
5 Applicable document types for ISO 20271 series . 3
6 Exploring applicability and extension to additional document types . 4
7 Audience of the ISO 20271 series . 4
Bibliography . 5

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 171, Document management applications,
Subcommittee SC 2, Document file formats, EDMS systems and authenticity of information.
A list of all parts in the ISO 20271 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Digital document files vary greatly in type and complexity. They range from simple binary stream files
to text-based files readable by humans, machine-interpretable files, and files that, while human-readable,
require interpretation and re-expression through complex logical structures and relationships.
Textual document file formats can take various forms, including simple binary or text-based structures
and more complex packaged formats that encapsulate multiple components, such as content, metadata
and resources, within a single container structure. Many modern document formats adopt such packaged
formats.
Ensuring long-term preservation and accessibility of these digital documents can be challenging, primarily
due to technical obsolescence, format incompatibilities, or software/hardware dependencies, such as:
— file format compatibility issues:
— file formats are no longer supported;
— new software fails to open correctly files created by the older versions of the same software (no
backward compatibility);
— reliance on proprietary formats rather than on standardized open formats can increase the risk of
format obsolescence and make preservation efforts more challenging e.g. due to inaccessibility of
detailed specifications, unavailability of usable software for handling the formats, or IPR-related
issues;
— limited adoption and support of formats:
— formats are not widely used or supported in the relevant domain;
— formats lack an active user community or support from multiple vendors;
NOTE 1 The use of formats that are widely adopted, based on open specifications, and supported by multiple
vendors can reduce the risk of obsolescence.
— software and hardware dependencies:
— files can only be opened on specific operating systems or software versions;
— compression algorithms, encryption technologies or cryptography-based features used (including
digital signatures, seals and time stamps) are no longer supported;
— lack of preservation policies:
— absence of policies or processes for the long-term preservation of document files;
— insufficient ongoing monitoring of file formats and storage media management.
NOTE 2 Other operational issues such as media ageing, physical corruption, environmental factors, and backup
planning are outside the scope of the ISO 20271 series.
The ISO 20271 series defines technical methods for the selection, verification and assessment of the subjects
of technical review concerning the obsolescence of textual documents. It provides a reference model and
framework for understanding textual documents and the properties that can be present within them.
The reference model addresses technical issues and provides assessment criteria to determine which
digital components (layers) or metadata are desirable or necessary for long-term preservation, as well as
to evaluate the suitability format for this purpose. To support this, the ISO 20271 series is structured as
follows (see Figure 1):
— This document (ISO 20271-1) defines the overall framework, scope and principles for the technical
review of textual document formats in the context of obsolescence. It also provides an explanation of the
structure and scope of the ISO 20271 series to enhance users’ understanding.

v
— ISO 20271-2 defines a reference model for textual document formats that can be used to analyse a textual
document file format. It also provides recommendations for preserving each layer of the format, including
content, metadata and presentation, ensuring long-term accessibility and integrity of the document.
— ISO 20271-3specifies properties that can exist in a textual document and provides reference markup for
representing those properties.
The ISO 20271 series is intended for use by organizations and practitioners involved in the creation,
management and preservation of textual documents. This includes developers of document formats,
system architects, archivists, and other stakeholders responsible for ensuring long-term accessibility and
sustainability.
The ISO 20271 series supports activities such as the analysis of textual document formats, the identification
and classification of document properties, the definition of preservation requirements, and the assessment
of long-term preservation risks.
In practice, the ISO 20271 series is intended to be applied as a coherent and iterative process.
ISO 20271-2 provides a reference model for analysing textual document formats by identifying layers and
associated properties.
ISO 20271-3 builds upon this model by defining a taxon
...