Calibre 4.0 has been released two years after version 3.0. It brings with it several features including new content server capabilities, a new e-book viewer which focuses on the text by hiding the tool panel in the right-click menu, and finally, the software has been moved from Qt WebKit to Qt WebEngine, but this does introduce some backward compatibility issues.
With Calibre 4.0, the content server has gained several new features. Users connected to Calibre via the content server now have the ability to edit metadata, convert books to other formats, and add and remove books and formats. To use the content server, just tap Connect/Share and start the content server. From there, you can connect to the provided address from other machines on the network.
Perhaps the biggest change in this update is the new e-book viewer. In previous updates, texts were surrounded by toolbars. Now, the toolbars have been removed and any options have to be accessed via a right-click. With the page turn button removed, you’ll now have to use the directional arrows to navigate through pages. One advantage to the new viewer is that it uses the same codebase as the in-browser viewer which will allow new features to be developed more easily.
With all the changes present in this update, there are now a few “minor” compatibility issues with older versions. One of the changes is to the book details panel, it no longer uses a full browser engine for rendering details. While this makes it faster it also means less HTML and CSS is supported so advanced styling in your comments may not work. Additionally, the markup needed for header and footer templates when converting to PDF has changed, more details on that can be found here.
Calibre is supported on all major operating systems, to download the e-book manager, head on over to the project’s download page for more information.