g validity. 
                        </p>
                        <p>  
                          The latest version of <a href="https://www.w3.org/publishing/epubcheck/">EPUBCheck</a>, namely <a href="https://github.com/w3c/epubcheck/releases/tag/v5.0.0">EPUBCheck 5</a>, validates EPUB 3.3. Earlier versions of EPUBCheck are extensively used throughout the industry for several years now, and act as “gatekeepers” in the publication workflow for the major EPUB platforms; it is to be expected that all th