Atticus prioritizes staying up to date with the latest ePub3 standards, widely adopted by eBook retailers for high-quality and accessible ePubs. However, certain devices or apps still rely on older conversion factors when manually loading eBooks (sideloading).
In such cases, we suggest opening the file on a device-specific eReader like Google Play Books or Apple Books instead of using the email-to-Kindle option, since the native apps will offer a better sideloading experience for readers.