ISO 26300 made office documents an open specification

What the standard defines

ISO/IEC 26300:2006, titled 'Information technology — Open Document Format for Office Applications (OpenDocument) v1.0', is described in ISO's own listing as defining 'an XML schema for office applications and its semantics', covering text documents, spreadsheets, charts, drawings and presentations, and built to be 'friendly to transformations using XSLT or similar XML-based tools'. That is a specific, checkable claim: the standard is a document structure, not a particular piece of software, and any program that produces files matching the schema can, in principle, be read by any other program that understands the same schema. ISO lists the standard's publication date only to the month, December 2006.

From a technical committee to an ISO standard

The format did not start at ISO. The OASIS OpenDocument technical committee's own record states that OpenDocument v1.0 was approved as an OASIS Standard on 1 May 2005, and that this version was then submitted for, and achieved, ISO/IEC 26300:2006 status. The committee's account also tracks what came after: a 2012 amendment folding in version 1.1, a three-part ISO/IEC 26300 revision in 2015 covering version 1.2, and OASIS's own version 1.3, published 16 June 2021. An open standard in this account is not a single frozen document; it is a specification with a defined process for revision, maintained by a multi-vendor committee rather than one company's release schedule.

What an open schema does not guarantee

Being openly specified answers one question and leaves another open. The schema being public means no single vendor can prevent another application from reading or writing it, which is the essential difference from a proprietary format whose full behaviour is undocumented outside the vendor that built it. It does not mean that every application implementing OpenDocument renders every feature identically; a spreadsheet formula, a complex style inheritance, or an embedded chart can still display differently between two conformant applications, because a schema defines structure and a great deal of rendering detail is left to the application. Lock-in, in other words, can survive the adoption of an open format if a document depends on quirks of one particular editor's implementation rather than the parts of the schema every implementation agrees on. This is an editorial reading of the two documents, not a claim either body makes directly.

• Is the file being saved in the open schema by default, or only available as an export option?
• Have the specific features used, such as complex styles or embedded objects, been checked in a second application before relying on them?
• Which version of the standard, 1.0, 1.1, 1.2 or 1.3, does the software claim to support?

An ISO standard changes who is allowed to build a reader or writer for a format; it does not, by itself, change how carefully any given application does so. The distinction is worth keeping when 'open format' is offered as a complete answer to the lock-in question.