ISO/IEC 29500-3:2015

Information technology — Document description and processing languages — Office Open XML File Formats — Part 3: Markup Compatibility and Extensibility

This Part of ISO/IEC 29500 defines a set of conventions for forward compatibility of markup specifications, applicable not only to Office Open XML specifications as described in Parts 1 and 4 of this Standard, but also to other markup specifications. These conventions allow XML documents created by applications of later versions or extensions to be handled by applications of earlier versions.

Technologies de l'information — Description des documents et langages de traitement — Formats de fichier "Office Open XML" — Partie 3: Compatibilité et extensibilité du balisage

General Information

• Status: Published
• Publication Date: 15-Jun-2015
• ICS: 35.060 - Languages used in information technology
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• Technical Committee: ISO/IEC JTC 1/SC 34 - Document description and processing languages
• Drafting Committee: ISO/IEC JTC 1/SC 34 - Document description and processing languages
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Jul-2025
• Completion Date: 15-Jul-2025

Relations

• Consolidated By: ISO 1833-18:2019 - Textiles — Quantitative chemical analysis — Part 18: Mixtures of silk with other protein fibres (method using sulfuric acid)
• Effective Date: 06-Jun-2022
• Revises: ISO/IEC 29500-3:2012 - Information technology — Document description and processing languages — Office Open XML File Formats — Part 3: Markup Compatibility and Extensibility
• Effective Date: 14-Dec-2013

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 29500-3
Fourth edition
2015-07-01
Information technology — Document
description and processing languages —
Office Open XML File Formats —
Part 3:
Markup Compatibility and Extensibility
Technologies de l'information — Description des documents et
langages de traitement — Formats de fichier "Office Open XML" —
Partie 3: Compatibilité et extensibilité du balisage
Reference number
©
ISO/IEC 2015
©  ISO/IEC 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any
means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission.
Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO/IEC 2015 – All rights reserved

Contents
Foreword .iii
Introduction .v
1 Scope . 1
2 Normative References . 2
3 Terms and Definitions . 3
4 Notational Conventions . 4
5 General Description . 5
6 Overview . 6
7 MCE Elements and Attributes . 8
7.1 Introduction . 8
7.2 Ignorable Attribute . 8
7.3 ProcessContent Attribute. 9
7.4 MustUnderstand Attribute . 9
7.5 AlternateContent Element . 10
7.6 Choice Element . 11
7.7 Fallback Element . 11
8 Application-Defined Extension Elements .13
9 Semantic Definitions and Reference Processing Model .15
9.1 Overview . 15
9.2 Step 1: Processing the Ignorable and ProcessContent Attributes . 16
9.3 Step 2: Processing the AlternateContent, Choice and Fallback Elements . 17
9.4 Step 3: Processing the MustUnderstand Attribute and Creating the Output Document . 18
Annex A (informative) Examples .22
A.1 Syntactic Examples . 22
A.1.1 General . 22
A.1.2 Ignorable Attribute: Multiple Prefixes Bound to a Namespace . 22
A.1.3 Ignorable Attribute: Non-conformant Use . 22
A.1.4 ProcessContent Attribute: Multiple Prefixes Bound to a Namespace . 23
A.1.5 ProcessContent Attribute: Non-conformant Use . 23
A.1.6 MustUnderstand Attribute: Non-conformant Use . 23
A.1.7 AlternateContent Element: Future Extensibility . 24
A.2 Semantic Examples . 24
A.2.1 General . 24
A.2.2 Ignorable Attribute . 24
A.2.3 Ignorable and ProcessContent Attributes. 25
A.2.4 Non-Ignorable and Non-Understood Namespace . 27
A.2.5 MustUnderstand Attribute . 27
©ISO/IEC 2015 – All rights reserved i

A.2.6 AlternateContent Element . 28
A.2.7 Ignorable Content Inside Application-Defined Extension Elements . 29
Annex B (informative) Validation Using NVDL .31
Bibliography .33

ii ©ISO/IEC 2015 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees established
by the respective organization to deal with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international organizations, governmental and non-
governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO
and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75% of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 29500-3 was prepared by ISO/IEC JTC 1, Information technology, Subcommittee SC 34, Document
description and processing languages.
This fourth edition cancels and replaces the third edition (ISO/IEC 29500-3:2012).
The major changes from the previous edition include:
 Specification of the core semantics in one place, and the interactions among semantic constructs
and/or the processing model.
 Removal of the specification of namespace subsumption
 Expansion of examples, in particular, by providing output documents
The intended semantics remains the same as long as namespace subsumption is not used.
The major changes in the third edition included:
 Removed all traces of the concept of markup editor
 Removed the attributes PreserveAttributes and PreserveElements
There were no major changes in the second edition.
ISO/IEC 29500 consists of the following parts, under the general title Information technology — Document
description and processing languages — Office Open XML File Formats:
©ISO/IEC 2015 – All rights reserved iii

 Part 1: Fundamentals and Markup Language Reference
 Part 2: Open Packaging Conventions
 Part 3: Markup Compatibility and Extensibility
 Part 4: Transitional Migration Features
iv ©ISO/IEC 2015 – All rights reserved

Introduction
ISO/IEC 29500 specifies a family of XML schemas, collectively called Office Open XML, that define the XML
vocabularies for word-processing, spreadsheet, and presentation office documents, as well as the packaging of
office documents that conform to these schemas.
The goal is to enable the implementation of the Office Open XML formats by the widest set of tools and
platforms, fostering interoperability across office productivity applications and line-of-business systems, as
well as to support and strengthen document archival and preservation, all in a way that is fully compatible with
the existing corpus of Microsoft® Office documents.
©ISO/IEC 2015 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 29500-3:2015(E)

Information technology — Document description and
processing languages — Office Open XML File Formats
Part 3:
Markup Compatibility and Extensibility (MCE)

1 Scope
This Part of ISO/IEC 29500 defines a set of conventions for forward compatibility of markup specifications,
applicable not only to Office Open XML specifications as described in Parts 1 and 4 of this Standard, but also to
other markup specifications. These conventions allow XML documents created by applications of later versions
or extensions to be handled by applications of earlier versions.
©ISO/IEC 2015 – All rights reserved 1

2 Normative References
The following referenced standards are indispensable for the application of this standard. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
standard (including any amendments) applies.
XML, Tim Bray, Jean Paoli, Eve Maler, C. M. Sperberg-McQueen, and François Yergeau (editors). Extensible
Markup Language (XML) 1.0, Fifth Edition. World Wide Web Consortium. 2008.
http://www.w3.org/TR/2008/PER-xml-20080205/. [Note: Implementations of this Part of ISO/IEC 29500 are
not required to support features of XML introduced by the Fifth Edition. end note]
XML Base, Marsh, Jonathan. XML Base. World Wide Web Consortium. 2009. http://www.w3.org/TR/2009/REC-
xmlbase-20090128/
XML Information Set, John Cowan and Richard Tobin (editors). XML Information Set (Second Edition), 4
February 2004. World Wide Web Consortium. http://www.w3.org/TR/2004/REC-xml-infoset-20040204/
XML Namespaces, Tim Bray, Dave Hollander, Andrew Layman, and Richard Tobin (editors). Namespaces in XML
1.0 (Third Edition), 8 December 2009. World Wide Web Consortium. http://www.w3.org/TR/2009/REC-xml-
names-20091208/
2 ©ISO/IEC 2015 – All rights reserved

3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply:
3.1
application configuration
set of names of understood namespaces
3.2
application-defined extension element
element defined by a markup specification, the attributes and content of which are not to be processed by an
MCE processor
3.3
markup configuration
set of expanded names of application-defined extension elements
3.4
markup specification
XML-based format specification that allows the use of elements and attributes in the MCE namespace
3.5
MCE processor
software used to process XML documents containing MCE elements and attributes
3.6
mismatch
incompatibility between the constraints specified by MCE elements and attributes, and the namespaces
specified by an application configuration
3.7
understood namespace
namespace, the elements and attributes of which a consuming application is able to process
©ISO/IEC 2015 – All rights reserved 3

4 Notational Conventions
The following typographical conventions are used in ISO/IEC 29500:
1) The first occurrence of a new term is written in italics. [Example: The text in ISO/IEC 29500 is divided
into normative and informative categories. end example]
2) The tag name of an XML element is written using a distinct style and typeface. [Example: The
bookmarkStart and bookmarkEnd elements specify … end example]
3) The name of an XML attribute is written using a distinct style and typeface. [Example: The dropCap
attribute specifies … end example]
4) The value of an XML attribute is written using a constant-width style. [Example: The attribute value of
auto specifies … end example]
Exce
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