I've found that some e-books in KF8 format work fine. For example, The Racketeer is an azw3 file and has a publisher-embedded font (Georgia). I can choose Publisher font or any of the other standard Kindle font options and they display correctly. I can also change line spacing and margin and the display responds correctly. This e-book is published by Doubleday/Random House Digital.
On the other hand, Winter of the World is also a KF8 e-book, but font selection doesn't work properly. It displays text in Caecilia regardless of font selection. It doesn't have a publisher-embedded font. Line spacing and margin controls work. This e-book is published by Dutton/Penguin.
This makes me think that the problem isn't the Paperwhite or a bug in the firmware, because the same device and firmware work fine with one KF8 ebook and incorrectly with another. Must be the way the e-book is formatted/encoded. Seems some publishers have figured this out while others are struggling with it.
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