Versatile e-book library management tool Calibre 0.8.69 adds theme switcher

Calibre is a versatile full-fledged e-book library management tool, combining, under a singular "roof", converting capabilities, metadata download, online news fetching, as well as a powerful yet easy-to-use e-book viewer, presenting the user an all-in-one e-book (MOBI, LIT, etc) centered application.

Weeks ago, Calibre received useful support for displaying mathematical operations inside e-books with an accurate rendering, functionality strengthened in the new 0.8.69 Calibre version, fix aimed at properly displaying mathematics that don't fit on a single line.

A definitely interesting addition in the new 0.8.69 release is the introduction of a theme switcher, handy button allowing the user to 1-click away switch between available previously-set themes (visual styles).

Consequently, while reading a book, clicking the left-side panel's Load a theme button, the user can select a theme from the summoned menu, action repeatable via the mentioned process.

In order to add/create a theme, navigate to Calibre E-book Viewer-->Preferences-->Theming-->Save, action that saves the modified E-book Viewer's style/theme containing modified configuration options, such as custom background and text color (available under Calibre E-book Viewer-->Preferences-->General-->Colors and backgrounds).

Along with the mentioned features, various enhancements and bug fixes, as well as new and improved news sources (History Today, De Volksrant, Metro UK, Countrylife, Birmingham post, etc), come to deliver a more up-to-date strengthened Calibre 0.8.69.

How do we install Calibre 0.8.69?
Add the following PPA (Precise)

sudo add-apt-repository ppa:n-muench/calibre

sudo apt-get update
sudo apt-get install calibre