Two years after the release of the third version, Caliber 4.0 was released.
Caliber is free software for reading, creating and storing books of various formats in an electronic library. The program code is distributed under the GNU GPLv3 license.
Caliber 4.0. includes several interesting features, including new content server capabilities, a new eBook viewer that focuses on text, and more.
The new version of the application switches from the Qt WebKit engine to the Qt WebEngine, although this created some problems with backward compatibility.
The content server in Caliber 4.0 has received several new features. Users now have the ability to edit metadata, convert books to other formats, and add and remove books and formats.
One of the big changes in this update is a new eBook viewer. In previous versions of the program, text was surrounded by toolbars. The toolbars are now removed and the options are accessible via right-click.
Source: linux.org.ru