The latest version of Calibre can be downloaded from Softpedia
The Calibre software provides some important functions for its users, like the ability to read, edit, and manage eBooks. The developer has issued a new update and the new version brings a few major features.Even if people mostly use Calibre for converting eBooks from one format to another or as a reader, the application is also capable of editing books as well. This new function was implemented recently and the developer is still adding features and fixes for it.
One of the biggest improvements in this latest update is the support that has been added for third-party plugins, which can really extend the editor's options.
According to the changelog, a --for-machine option that causes the output to be made in a form more easily parsed programmatically (it uses ASCII field and record separators) has been implemented, the ISSN identifiers are now converted back into links to the periodicals page on worldcat.org, when the user is re-arranging the toolbars inside an individual file editor the new toolbar layout is now saved, the changed layout is now applied to all open editors of the same type, the undo / redo / cut / copy / paste buttons on the editor toolbar are now also configurable, and editing xpgt (Adobe Page Template) files as XML is now possible.
Also, it's now possible to launch the saved searches dialog and to be added to the global toolbars, an option has been added to make clicking on the author name search in the Calibre library for the author instead of opening the Wikipedia page for the author, the published date is now properly managed when merging book records, an error that occurred when trying to embed metadata in corrupted MOBI files or files of other types that were marked as MOBI in the library has been fixed, and the soft-hyphens in the text are no longer rendered as hyphens.
Installing the latest version of Calibre is quite easy, as the developer provides a simple script to do all that. It should be platform-independent, but some users might not be able to run it. If you find yourself in that position, you can download the source package and try to compile it yourself. It has many dependencies, so that might be an issue. The only other alternative is to get it from the repositories, but you might not get the latest release.
You can also check out our review of Calibre and download Calibre 1.46 from Softpedia, but keep in mind that this is just the source.