Kobo iOS application and iOS 6
If you have a device that is running iOS 6, and you are using the Kobo iOS application, you should upgrade to v5.7 or later. The current version is 5.7.1.
If you do not upgrade then you will experience an issue whereby text in all books will overflow at the bottom of the page. You will also experience an issue whereby all chapters will only be a single page in length and turning a page will instead change the chapter.
Both of these are issues with version 5.6 or earlier of the app and iOS 6, and are addressed in version 5.7 or later of the app