I've been a insatiable reader for 70 years, but my vision has degraided to the point that I can't read most printed books. Kindle has been a blessing, since I could select the largest font and see well enough to read.
However, a recent update to my Kindle Fire HD 8 Fire OS 7.3.2.7, has reduced the maximum font size to either 6 or 7 pt, which I can't read. I spent a couple of hours unsuccessfully attempting to resolve the problem, before retrieving my backup Kindle (an older Paperwhite.) I found it too, had received a recent update, and now the font was too small for me to read.
If I can't fix this issue, I'll have to buy a non-Kindle tablet, which will allow me to set the font large enough to read.
In thinking about why Amazon would make such a problem, as an author with over 20 books on Amazon, I thought of an evil possibility.
What if, some Amazon bean counter had an idea of how to reduce Amazon's cost paid to authors for KDP page reads. By signifinatly reducing the maximum font size, a book will have fewer pages, and less KDP page reads.
I'm sure this is just a technical issue that will be resolved as soon as Amazom can correct it. We authors know that Amazon only has our best interests in mind, except maybe for that one bean counter...