Numeric book contains EPUB2 compatibilities when necessary
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
Prevent fallbacks for HTML5 interactions
apply a reset to HTML5 elements used so they don’t pose a problem for solutions that don’t 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 information for HTML5 elements (article, aside, details, figure, figcaption, footer, header, nav, section)
Check CSS Sheets if layout is rendered using media queries