Lightning 1.0rc2 is available, with full offline support

I’d like to present you with Lightning 1.0rc2. You can find it at its new location on the beta channel (If you still get 1.0rc1, then please try again in a few hours when the page cache has been updated).

There is a big new feature in this release which needs your testing. Thanks to the hard work of Mohit, who has joined us through the recent Google Summer of Code, we have extended the cache with full offline support, which means you can write your events while in offline mode. If you are using a CalDAV calendar, it will even retry events that failed.

If you encounter any issues, please file a bug at

Note, if you are using the cache with the Provider for Google Calendar, please stay tuned. I will soon post a development version of the provider containing a patch that corrects offline support.


  1. Just wanted to quickly try it, but could not get it to work.
    1. One has to explicitly tell Thunderbird to go in offline mode for the feature to become active.
    2. I created an event. Then I switched back to online mode.
    Now I get:
    “Status-Code: 412, Voraussetzung nicht erfüllt.
    Precondition FailedPrecondition FailedRequested resource has a matching ETag.”

  2. A “big new feature” in Release Candidate 2 phase ???
    I’m sorry but … I can’t understand it.

  3. First of all thank you very much for the effort you put in the handling of event invitation.
    It is a bit too late, because already with one of the last releases you changed the behaviour for event invitations. But this was really a pain in the ass, that one was not able to see wether people accepted or declined an invitation. Now with the new email header and the possibility to see the invitee’s status lightning became much more useful.

  4. Not compatible with Thunderbird 7.0.1 in which I am still using beta7, what version of Thunderbird is that compatible with?

  5. Hi Felix,
    May I know how to reproduce the steps for your case, also which Calendar type were u using? Caldav or ICS ?

  6. @Pascal Chevrel: You need Thunderbird 8. In case you are using Ubuntu there is a repo for that…

  7. Jose Luis Rodriguez Garcia

    Where can I download the source code?
    I would like to try in my system:
    – NetBSD 5.1/x86 with Seamonkey 2.3.1

  8. Adding multi-day all-day events, or editing existing ones, doesn’t appear to be possible under 1.0rc1 or 1.0rc2.
    For example, if I want to add an all-day event for November 15 & 16, I cannot enter different days for the start and end date. If I adjust the start date, Lightning changes the end date and vice-versa.
    Even if I have an existing multi-day event from a previous iteration of Lightning, let’s say from Nov 15-16, and want to extend the end date to the 17th, I can’t do it. When I change the end date to the 17th, Lightning changes the start date to the 16th. If there’s a way around this, I sure as heck can’t figure it out. The only way I’ve been able to fix events like this is to make the change via Firefox in Google Calendar.

  9. Offline support appears to work pretty robust! Al least under caldav with google calendar. (Although error log shows this a lot: this.mItemInfoCache[] is undefined. Source: [profile location]/…/calDavCalendar.js, Line: 691)
    Interface suggestion, instead of Cache (experimental): “Make available offline. Building of database can take several minutes.”
    I think making it default is not a good idea, yet.
    And unless bug 412914 can be fixed, I would add: “Does not work with ical calendar.” The (really really!) slow startup makes ical unusable (although it does work in the end).

  10. @BobT
    try to click on the button with a “chain” image on the right side of the start and end datepickers in the dialog.
    As the tooltip says (leave the mouse a fraction of second over it) it allows to keep the event duration when the user changes the end date.
    i.e. when the chain image is “linked”, it allows to obtain with the end date the same behavior that already has the start date.

  11. Cas,
    we’ll look into the error you mentioned, thanks for reporting! We’ve changed the label to “Cache”, although “Make available offline” would have been better, I agree. I’ll see if I can change this for a future version.

  12. Hi,
    It’s not a bug for everyone but for me I want to see all event (private or not, all day or not) in the minimonth.
    So please, at least making an option for this bug :

  13. I can’t install the b7 because it is not compatible with version 3.1.15. I can’t keep updating my Thunderbird because with the new Mozilla ridiculous upgrade every two weeks B.S. my antivirus email scanner plug in can’t keep up with the changes. It isn’t even compatible with Thunderbird 6 yet. And I don’t think the antivirus people are unreasonable, I think the Mozilla managers are retards and their release schedule is f’ing idiotic.
    No antivirus company can devote a resource to constantly keeping up with Mozilla’s stupid upgrade schedule. So I can’t upgrade all the time.
    Does this mean I will never be able to use the lightning integrated calendar. Not meaning to sound too rude (although I will if it helps smarten people up there), but if this is the case Movilla will force me to move back to Outlook since I need an integrated calendar, and they are making it impossible for antivirus companies to keep up with the release numbers. BTW I have a paid for antivirus/firewall suite, not freeware: ESET.
    And no, I don’t want to hear from Mac or Linux users. I haven’t had a virus on my PC for more than 12 years and attribute that to good security practices including always having the ability to have incoming email scanned.