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These Release Notes cover what's new, download and installation instructions and known issues for Lightning 0.8 Please read these notes and the bug filing instructions before reporting any bugs to Bugzilla.

What's New in Lightning 0.8

Lightning 0.8 is the latest release of our calendar extension for Mozilla Thunderbird®. We recommend that all users upgrade to this latest version.

The following features have been added to Lightning 0.8:

  • Lightning 0.8 introduces a task mode (Screenshot) that contains the following features
    • Quick display of current tasks
    • Task preview pane displaying task parameters like the description, from date, due date, category, etc
    • Possibility to filter displayed tasks (today's tasks, overdue tasks, completed tasks, etc.)
  • New icon set and reworked menu structure that only offers the user those options that are currently available to him in calendar or task mode
  • Lightning now contains an event list (also known as "unifinder"), which allows the easy selection and sorting of current, future and past events. The unifinder can be easily enabled or disabled by using the "Find events" button on the Calendar toolbar
  • Category colors are now shown next to an event box, giving users a much better overview of their differently categorized events
  • Events with alarms now have a visual indicator showing an alarm bell
  • A totally overhauled alarm dialog
  • Easy conversion of mails, events and tasks into each other. The mode toolbar icons on the left side now function as drop targets, which allows you to convert an e-mail to an event or tasks (or vice versa), just by dragging an e-mail to the calendar icon on the left
  • Visual overhaul for the today pane
  • Lightning now recognizes the timezone definitions in .ics files created by other applications. This fixes the longstanding issue of Lightning miscalculating the date or time of events contained in those files
  • The timezone guessing has been significantly improved
  • Lightning now contains experimental support for viewing remote calendars offline. This feature has known bugs and is included for testing purposes only
  • Lightning contains several performance fixes, which should improve working with larger calendar files
  • You can now define for each of your calendars, whether you want to be notified of alarms for events in these calendars or not
  • Special builds with support for Sun Java Calendar Server (lightning-WCAP) are no longer available as the base extension package now contains all the necessary code
  • Thunderbird 1.5.0.x builds are no longer supported. Users of Thunderbird 1.5.0.x are strongly encouraged to update to Thunderbird 2. Please use the "Check for Updates..." option in the help menu to get the update
  • A full list of changes that have gone into this release can be found on The Rumbling Edge website

Release Date: April 04, 2008

Downloading and Installing

Downloading Lightning 0.8 provides Lightning for Windows, Linux, Solaris, and Mac OS X in a variety of languages. Windows users must have Windows XP or later.

Windows releases prior to Windows XP are working but may display event times erroneously due to outdated timezone on the operating system level. This can be fixed using unofficial patches. Users should read the known issues section for more information.

To get Lightning 0.8, download it here.

For builds for other systems and languages not provided, see the Contributed Builds section at the end of this document.

Installing Lightning

Lightning runs as an extension for Mozilla Thunderbird 2.0.0.x

IMPORTANT: If you have been using the old Calendar Extension, be sure to backup the ICS file that it put in your profile directory, and uninstall the Calendar Extension before installing Lightning. After you have installed Lightning, you can then import your old events and tasks from the backed up ICS file.

  1. Right-click (Control-click on Mac) the download link and choose "Save Link As..." to download and save the .XPI file to your your hard disk
  2. In Mozilla Thunderbird, under the "Tools" menu, open the "Add-ons Manager"
  3. Click the "Install" button, locate and select the .XPI file you downloaded in step 1, and click "OK"
  4. Restart Mozilla Thunderbird

Known Issues

This list covers the major known issues with Lightning 0.8. Please read this list before reporting any new bugs.

All Systems

  • After updating to Lightning 0.8 you should execute the "Restore Default Set" command from the Customize Toolbar dialog as previously added Calendar-specific buttons on your mail toolbar may no longer work as expected
  • Lightning 0.8 will attempt to guess your timezone on startup. As this is only a best guess, you must manually set the timezone in the Thunderbird Preferences/Options dialog before entering data. Not doing so may cause events to appear at the wrong time
  • The experimental support for viewing remote calendars offline has various known issues in the area of performance and calendar data display. It does not support the offline editing of events and tasks
  • It is impossible to load several calendars with different passwords on the same server. (bug 247486)
  • Portions of attachments on events and tasks may be lost when uploading to a remote calendar. (bug 319909)
  • "By weekday" and "by day" recurrence types (such as "recur on the last weekday of the month") are not supported. (bug 322458)
  • Concurrent editing of remote calendars by multiple users can lose data. (bug 329570)
  • Enabling the "Automatic proxy configuration URL" preference will cause remote calendars to fail to load on startup. To workaround this bug, execute "Reload Remote Calendars" after the application has started up or use "Manual proxy configuration". (bug 338527)
  • There are intermittent issues when modifying occurrences of recurring events via iMIP and Copy/Paste. (bug 354578)
  • Under some instances the "Do you want to save your changes" dialog does not come up when editing events in the event dialog. (bug 364387)
  • Due to the complexity of the Daylight Savings Time rules for the /Asia/Jerusalem timezone, .ICS files which contain events in the /Asia/Jerusalem timezone may fail to import into Microsoft Outlook 2003 (as well as earlier versions). These files should import successfully into Microsoft Outlook 2007. (bug 367378)
  • Events deleted in Lightning will not be deleted on a OpenXchange server unless "enabledelete=yes" is added as a GET parameter. (bug 369076)
  • Multiple windows of the same single event can be opened from the Agenda, the task list and the unifinder. (bug 373251)
  • E-Mail invitations generated by Lightning are not recognized by Outlook 2003 due to the mail MIME structure. (bug 377761)
  • The event box tooltips will lose the last 1 or 2 characters of the longest line on Windows with the Luna theme or some 3rd party theme. (bug 390313)
  • Creating two events or tasks with a length of zero minutes on the same date and on different calendars will lead to only one of those events or tasks being visible. (bug 394004)
  • Lightning 0.8 will only display the email invite messages from other parties, if "View -> Display Attachments inline" is set in Thunderbird. (bug 403768)
  • Local calendars might break, if you upgrade from a 0.8pre nightly build to the 0.8 release build. See this newsgroups thread for information on how to fix this. (bug 410931)
  • Adding events or tasks to a CalDAV calendar whose display has been turned off, will not re-enable the display of that calendar. (bug 421986)

Linux and Solaris

  • Because of bugs in older X servers, there are unavoidable race conditions in drag and drop in month view on Un*x desktops, which may lead to a complete freeze. This has been noticed especially in situations where people were connecting to a remote X session (bug 348009)

Mac OS X

  • The 'Preferences' and 'Quit' menu commands are deactivated in calendar mode and task mode. As a workaround you can access them by switching to mail mode first and then choosing these menu commands (bug 409845)


  • Printing a calendar does not work on the first attempt, but will work on the following attempts. (bug 351581)
  • Due to the lack of official timezone updates from Microsoft for the following Windows releases
    • Windows 98
    • Windows 98 SE
    • Windows ME
    • Windows NT 4.0
    • Windows 2000
    you may experience that events will be shown off by an hour.

    There are unofficial patches available for Windows 98/98 SE/ME and for Windows NT 4.0/2000.
    Note: These patches are not provided by the Mozilla Calendar Project and the developers can not guarantee that these patches will work as intended and do not have unintended side-effects.

The following resources contain useful information about Lightning:


Thanks to the hard work of our localization teams, Lightning 0.8 ships with the following locales pre-installed:

  • Basque - Euskara
  • Catalan - Català
  • Chinese (Simplified) - 中文 (简体)
  • Czech - Čeština
  • Danish - Dansk
  • Dutch - Nederlands
  • English (United States)
  • French - Français
  • Georgian - ქართული
  • German - Deutsch
  • Hungarian - Magyar
  • Irish - Gaeilge
  • Italian - Italiano
  • Japanese - 日本語
  • Korean - 한국어
  • Lithuanian - lietuvių
  • Macedonian - Македонски
  • Norwegian (Bokmål) - Norsk bokmål
  • Polish - Polski
  • Portuguese (Brazilian) - Português (do Brasil)
  • Portuguese (Portugal) - Português (Europeu)
  • Russian - Русский
  • Slovak - Slovenský
  • Slovenian - Slovensko
  • Spanish (Latin America) - Español (de América)
  • Spanish (Spain) - Español (de España)
  • Swedish - Svenska
  • Turkish - Türkçe
  • Ukrainian - Українська мова

Contributed Builds

These are unofficial builds and may be configured differently than the official builds. They may also be optimized and/or tested for specific platforms.

Solaris builds (contributed by Sun Microsystems)

OS/2 builds

Linux x86-64 builds

Other Systems

Builds for platforms other than the trio officially offered by can be found on the FTP site.

Previous versions of the Release notes: 0.7 | 0.5 | 0.3.1 | 0.3 | 0.1