InDesign 20.4: Major Accessibility Advances

/in /by
InDesign logo

The InDesign Expert Group continues to drive significant improvements in EPUB accessibility with the release of InDesign 20.4. This latest update builds on collaborative work of the InDesign Expert Group which includes Richard Orme (DAISY), Gregorio Pellegrino (Fondazione LIA, technical lead), Jonas Lillqvist (Celia), and Laura Brady (eBOUND).

New Accessibility Features

Native MathML Export

The most significant addition in InDesign 20.4 is the ability to export mathematical expressions as native MathML in EPUB files. This long-awaited feature builds on the MathML support introduced last October in version 20.0, and makes it possible to create math content that is accessible to screen reader users—both through speech and braille.

MathML is designed to work with assistive technologies and supports semantic navigation of expressions. It can also adapt to visual settings such as larger text and high-contrast modes, which is beneficial for many readers with print disabilities. However, support for visual rendering of MathML varies between reading systems, and may still have limitations in practice.

The reflowable EPUB export dialog now includes an option to choose between exporting math as SVG or MathML, under the Object tab.

Note: The default export setting is SVG with hidden MathML for accessibility. To get the full advantages of native MathML, consider selecting MathML when exporting.

The Reflowable Layout Export Options Dialog highlighting the option to export as SVG or MathML

MathML export is an important step forward, but it is not yet perfect. At the moment, it includes MathJax dependencies that are not necessary for most modern EPUB reading systems, and both formula scaling and color adaptation in different reading environments require refinement.

Enhanced SVG Support with Image Tags

InDesign 20.4 introduces a new “Image Tags” option for SVG export, allowing SVGs to be exported using standard HTML <img> tags while preserving their vector format. This addresses the long-standing issue where SVGs are converted to raster PNG images by default.
Key improvements:

  • SVGs can now be exported with alternative text using the alt attribute
  • Decorative SVGs are correctly marked with alt=”” and role=”presentation”
  • Vector images remain scalable without quality loss

To export an image using this option, open the Object Export Options panel. Choose “Use Existing Image for Graphic Object”, and set “Use SVG As” to “Image Tags”.

The Object Export Options Panel highlighting the option


Or, to apply this setting to all images, configure it in the EPUB Reflowable Export Options dialog. Select “Use Existing Image for Graphic Objects”, and set “Use SVG As” to “Image Tags”.

The Reflowable Layout Export Options Dialog

Enhanced Navigation File Titles

InDesign 20.4 completes the page title implementation with proper handling of the navigation file. The EPUB export now generates appropriate <title> elements for special files that were previously using generic placeholders.
Navigation file improvements:

  • The cover file now uses localized “Cover” text instead of a filename-based title
  • The navigation file (toc.xhtml) uses either a user-defined title from the TOC style (if specified) or, as a fallback, localized “Contents” text

This enhancement ensures that users of assistive technologies receive meaningful context when navigating through EPUB files, particularly when moving between the cover, table of contents, and content pages.

Nested List Documentation

A significant development workflow improvement has been documented: users now know how to create nested unordered lists (ul within ul) using left indent settings. When consecutive list items have increasing left indents, InDesign correctly generates nested HTML list structures.

This information has been officially documented in the InDesign Help pages, specifically in the “Bullets and Numbering – InDesign Help” section, following requests from the accessibility community.

Impact on Accessible Publishing

These updates represent an important step forward in making InDesign a more powerful tool for creating accessible EPUBs. The native MathML support particularly addresses a critical gap for educational and scientific publishing, while the improved SVG handling ensures that visual content remains accessible across different reading environments.

The Expert Group continues to work closely with Adobe’s InDesign engineering team to address remaining accessibility challenges and implement best practices for inclusive publishing.

For this reason the InDesign Expert Group welcomes feedback on these new features and continues to prioritize accessibility improvements in future releases. Publishers and content creators are encouraged to test these features and share their experiences through Adobe’s feedback channels.