Andrys Basten of KindleWorld noticed last night that Amazon had released a new version Kindle 4PC. The only major change to K4PC 1.7.1 is that it adds support for PDF. Actually, it would probably be more accurate to say that Amazon tweaked PDF support so it worked better.
I was told last week that Amazon had added PDF support in the 1.7.0 update (at the same time as they added Kindle Print Replica format). Now, I'm sure it was there, only I didn't notice because my copy of K4PC couldn't read the PDF I tested. I had assumed that it simply didn't support PDFs, when the problem is that it only supports most PDFs.
But on the upside, you can use most of the common PDF tools in K4PC now, including zoom, scroll, highlighting, dictionary/Google/search, and you can attach text notes. You can download the new version from Amazon.
PDF support does raise an interesting issue, though. I had argued last week that Amazon wouldn't adopt Epub because they hadn't adopted PDF. Well, it turns out that they have, and that negates my argument.
The KPR file is a wrapper for a PDF file. Now that Amazon will also let you open a PDF in K4PC, I do not think the wrapper is an attempt to disguise the PDF. No, it's simply how Amazon added their own DRM on top of the PDF file. If and when Amazon adopt Epub, they still won't admit to selling you one. But there's a good chance that they will let you read your own (DRM-free) Epubs. That is a close second to my desired outcome.
But before you get too excited about Epub, note that Amazon adopted PDF because they wanted to go after the textbook market. I don't think they will adopt Epub unless they have a similarly really good reason to do so.
On the other hand, the library ebooks support (that the Kindle is going to get this fall) could be the reason for Amazon to adopt Epub. Who knows, we might wake up one day next month and find that Amazon have turned the world upside down again.