Since 2008, Catspaw Dynamics has been building ebooks to a higher standard. With our feet planted both in print and digital, we endeavour to bring a better reader experience to modern devices. Without pushing a specific platform, we examine the competing ebook formats and the devices they run on, outlining their strengths and weaknesses.


ePUB Logo

With ePUB 3 superseding ePUB 2 in 2011, eBooks benefitted from an updated standard based on a subset of HTML 5. For readers, this meant better page layout and typography. Combined with faster devices with larger memories, we’re that much closer to eBooks which rival their print versions.

ePUB 3 is used by most non-Kindle readers, including Apple iOS and MacOS Books, Kobo, Nook and other apps which run on Android, Kobo, MacOS and Windows.

The best reading experience is in Apple’s Books apps. They’re the most standards-compliant programs out there currently.

On some devices/programs you will need to choose Publisher or Original Fonts to have the reading experience we intend.

Testing is done currently on:

Android: Bookari Ebook Reader Premium, Gitden Reader, Infinity Reader, Kobo Books, Lithium Pro
iOS: Books, Bookari Ebook Reader Premium, Gitden Reader, Kobo Books
Kobo: Aura H2O, Touch
MacOS: Books
Windows: Icecream Ebook Reader

If you download one of our ePUBs onto an older device, OS or program and it does not display properly, you may only have an ePUB 2-compatible device or program. And not all ePUB 3 readers are created equal. Here are the ones we’ve used that just don’t measure up:

Bibliovore, Bluefire Reader, Bookviser Reader, ePub3 Reader, FBReader, freda, Kitabu, Legimi-ebookibez, Sumatra PDF

Windows especially has a lack of ePUB 3 readers that format the page properly and use the typography we’ve specified. The only one we’ve found so far that provides an acceptable reading experience is Icecream Ebook Reader, which is most likely why its paid version is the most expensive of any eBook reading software out there.

Unfortunately, Barnes & Noble’s Nook devices and apps are not available nor supported in Canada, where we are. As a result, we do not test for Nook.


KFX Logo

KFX is Amazon/Kindle’s latest format, supported on devices which run Kindle firmware v5.8 and newer.

KFX is built on ePUB 3, but with a Kindle proprietary wrapper that can contain DRM (Digital Rights Management) copy protection. We convert from ePUB to KFX, and the reading experience should be comparable to the best ePUB 3 devices and programs.

You will need to choose Publisher Fonts to have the reading experience we intend.

Testing is done currently on:

Kindle: Paperwhite 2018
Android: Amazon Kindle
iOS: Kindle
MacOS: Kindle
Windows: Kindle


Kindle Generations

Three generations of Kindle software. The Kindle 4 (left) runs v4.1.3, the original Paperwhite (middle) runs v5.6.1.1, and the 2018 Paperwhite (right) runs v5.11.1. To read ebooks in Kindle’s KFX format, your Kindle device or app must be v5.8 or greater.


KF8 Mobi Logo

KF8 was Amazon/Kindle’s first attempt at wrapping an ePUB 3-based file inside a proprietary wrapper. While it achieves generally good results, it has its limitations compared to ePUB 3 and KFX. Any Kindle device with firmware less than v5.8 uses KF8/MOBI.

You will need to choose Publisher Fonts to have the reading experience we intend.

Testing is done currently on:

Kindle: Paperwhite 2012


For Kindle’s oldest devices, the KF8/MOBI format supplies the MOBI file alongside the KF8. MOBI was developed by the now-defunct Mobipocket SA, and its technology was purchased by Amazon for Kindle software. MOBI has many limitations as far as layout and typography go, providing only the most-basic reading experience. You’ll get all the text, but will miss out on the niceties of designer-specified typefaces and other choices meant to enhance the reading experience.

The Publisher Fonts option on this generation of Kindles is buggy at best.

Testing is done currently on:

Kindle: Kindle 4


Your comments and questions are welcome, and if you’d like to enquire about us designing your print publication or ebook, there’s email in the footer.