The latest version of Calibre can be downloaded from Softpedia
The Calibre eBook reader, editor, and library management software is now at version 2.1.0 and it bring numerous fixes after the huge release that was made only a week ago.The Calibre developer decided to go straight to version 2.0 last week and he made quite a few changes and improvements to the software that really warranted that jump. As it was to be expected, such a big update also brought with it quite a few problems. This update is about bug fixing, although Calibre 2.1.0 also packs a few new features as well.
According to the changelog, support has been added for the new Kobo Aura H2O and firmware 3.8.0, the driver for HTC C. has been added, a new tool is now available to easily test templates (users will find it in Preferences->Toolbars to add the tool to one of the calibre toolbars), the users are now allowed to use the full template language including all custom columns, soft-hyphens are no longer causing rendering artifacts with some fonts due to a bug in Qt 5, and the Ctrl+Home/End key combination is now capable of selecting the first/last book.
Also, the header and footer templates for the PDF output are now working properly, an error that occurred when converting EPUB/HTML files that contain invalid margin or padding declarations has been fixed, Calibre is no longer crashing on startup on some Linux systems when used with --detach, numerous Qt 5 related bugs have been fixed, the optional system tray icon has been disabled because of bugs in the system tray icon implementation in Qt 5 on Linux systems, and a regression in 2.0 that changed the speed of scrolling with the mouse wheel in flow mode has been fixed.
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.
Users can also download the source package and try to compile it. 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 2.1.0 from Softpedia, but keep in mind that this is just the source. If you do happen to find any bugs, please make sure to contact the developer and let him know.