If you use calibre to manage your ebook library and are fond of its ebook reading function, you might want to hold off on the latest update.
Calibre 4.0 was released on Friday. According to the changelog, one of the major improvements/changes was a new ebook viewer:
The calibre built-in E-book viewer has been completely rewritten. The new design emphasizes the book text, with no visible controls. The viewer now also shares a codebase with the in-browser viewer which will make developing new features such as the upcoming support for annotations much easier.
What that means is that the new viewer is missing the left sidebar menu found in the old viewer. You can see the new viewer in action in these screenshots.
The new viewer is reportedly faster, but that comes with a trade off; the footnotes for the changelog mention that the new viewer might break any fancy formatting notes or comments in your metadata: "The Book details panel now no longer uses a full browser engine for rendering. This makes it faster and less resource intensive, however it supports less HTML and CSS, which means if you used advanced styling in your comments it may not fully work". (Note: that applies to the metadata, not the contents of a book, so it's really not a big deal.)
Nevertheless, in spite of the improvements, users are not happy with the changes to the interface. I was catching up on new discussion threads over on MobileRead this morning when I found multiple complaints in the calibre forum about the new app. For example:
I also have reverted to 3.48 from 4.0.
I miss the page numbers (rather than a %), the easy fast search for a dictiorary or web search, and the quick click for changing font sizes.
I have no issue with the small amount of margins taken up by the left and top toolbars--and they are immediately accessible.
A number of users are so unhappy that they found a way to circumvent the changes. Some reverted to an older version of calibre, but others instead installed a second (and older) copy of calibre, and hanged various settings so that ebooks were opened using the older calibre's ebook veiwer.
You can find more details on that over on MobileRead.
How do you plan to respond to the change?
Me, I plan to continue to use the version of calibre I have right now (3.41). It's stable, and does everything I need, so there's no good reason to replace it.