Calibre E-book App 5.0 Released with Highlighting & Dark Mode

Last updated: October 1, 2020

Calibre, cross-platform open-source comprehensive e-book software, released version 5.0 with some great new features.

Calibre 5.0 features highlighting in the E-book viewer. Simply select text and click the Highlight selection button. It can be colors, underlines, strikethrough, etc. and has added notes. All highlights can be both stored in EPUB files and centrally in the Calibre library.

The new release also feature Dark mode support. On Windows and Mac, it is activated automatically based on OS settings. In Ubuntu Linux, launch the software in dark mode via CALIBRE_USE_DARK_PALETTE=1 environment variable.
Other features in the release include:

  • Python 3 port. Some third-party plugins will no longer work, until they are also ported to Python 3.
  • Support both vertical and right-to-left text.
  • Enhanced search in the E-book viewer
  • Support bookmarking in content server’s in-browser viewer

How to Install Calibre 5.0 in Ubuntu Linux:

Open terminal (Ctrl+Alt+T) and run command to download & install the official installer script:

sudo -v && wget -nv -O- | sudo sh /dev/stdin

Once installed, open it from system application launcher and enjoy!

Enable Calibre Dark Mode in Ubuntu:

To temporarily open the e-book reader in dark mode, simply run command:

export CALIBRE_USE_DARK_PALETTE=1 && calibre

To make it permanent, run command to edit the .desktop file and do:

  • add env CALIBRE_USE_DARK_PALETTE=1 at the beginning of the values of “TryExec” and “Exec”.
  • remove --detach flag, or the shortcut icon will disappear.

How to Remove Calibre E-book software in Linux:

To remove the software, open terminal and run command:

sudo calibre-uninstall


I'm a freelance blogger who started using Ubuntu in 2007 and wishes to share my experiences and some useful tips with Ubuntu beginners and lovers. Please comment to let me know if the tutorial is outdated! And, notify me if you find any typo/grammar/language mistakes. English is not my native language. Contact me via [email protected] Buy me a coffee:

12 responses to Calibre E-book App 5.0 Released with Highlighting & Dark Mode

  1. hi
    were can i find the CALIBRE_USE_DARK_PALETTE=1 environment variable ?
    (i am on linux mint)

  2. I followed instructions but the shortcut still disappeared and the app didn’t launch in dark mode anyway. had to change env to export to get it to work, but the shortcut in app menu is still missing.

  3. Hi, in the latest version on Ubuntu 20.04 the ‘calibre-gui.desktop’ is in this directory: /usr/local/share/applications/’calibre-gui.desktop

    • In my 20.04.1 the Calibre 5.4 location is
      It refuses to start, possibly lacking XCB Library

  4. In my Ubuntu 20.04.1 with Calibre 5.5.0, I replace the line “Exec=calibre –detach %U” with the following command “Exec=env CALIBRE_USE_DARK_PALETTE=1 calibre –detach %U”, and now I run the application in dark mode without problems

    • Using Mint 19.2 with Cinnamon and tried what José Cofré said above and it didn’t work. Calibre doesn’t display dark theme at all.

    • I have Ubuntu 20.04 and calibre 5.11 and your solution works fine for me. Thank you!

  5. I remove the tryExec line and replace exec for Exec=env CALIBRE_USE_DARK_PALETTE=1 calibre %U. Works!!

  6. in ubuntu 20.04 this works for me :

    Exec=env CALIBRE_USE_DARK_PALETTE=1 calibre %F

    if i change TryExec the application icon will disapeared.