Many users still have older reading devices and software that do not support EPUB 3. By ensuring compatibility with EPUB 2, publishers can ensure that their digital books are accessible to a wider audience.

Objectives

• Ensure playback on older devices

Implementation

• Use EPUB2 cover metadata
• Include a table of contents in “toc.ncx” format
• Add EPUB2 guides to convert EPUB3 landmarks
• Apply CSS rules to HTML5 elements to ensure they display correctly in engines that do not natively support them
• Place media queries in a separate CSS sheet

Control

• Check the preference in the ‘opf’ file of the metadata ‘cover’
• Check toc.ncx file layout
• Check the presence of a section in the opf file
• Check Override Content Presence for HTML5 elements
• Check CSS Sheets if layout is rendered using media queries