How are Lightning users doing in terms of Thunderbird usage

Six month ago, I shared our usage statistics for Lightning with you, which showed that Lightning users on Thunderbird 3.x had surpassed Lightning users on Thunderbird 2.x for the first time.

Now it’s time to look at things again and I’m happy to report, that as of yesterday roughly 75% of our users now use a Thunderbird 3.x build as can be seen in the chart below.

It’s also important to note that nearly 60% are already using the latest Thunderbird 3.1.x builds, while users of the old Thunderbird 3.0.x series are decreasing fast. This is mostly due to the major update offers of Mozilla Messaging for users of Thunderbird 3.0.x.

Major update offers have recently (last week) also started for users of Thunderbird 2.x, but haven’t really been unthrottled yet (throttling means, that currently only 1 in 5 users of TB2 gets a major update offer to Thunderbird 3.1.x). Once major update offers go out to every TB2 user, we expect their numbers to decrease much more heavily. The current state of things (showing the last six months) can be seen in the chart below:

As frequently noted in earlier articles, the ratio of Thunderbird 3.0.x and TB 3.1.x users is much higher on the weekends compared to the Thunderbird 2 users. The graphs show that very well.

For those interested: The “other” number contains users on older Thunderbird 1.5.x builds, SeaMonkey users and users, who have mistakenly tried to install Lightning into Firefox. Generally that number always fluctuates between 0.35% and 0.5% of our total active users.

I hope that you will find this as interesting as I do.


  1. How many ADU does Lightning have?

  2. Roughly 500,000 on the weekends and nearly 1,000,000 through the workweek at the moment. Detailed info is available at

  3. Hm, the obvious “weekly cycle” component of the curves seems to indicate that Tb2 is used more at work than at home — well, “enterprise” users are notoriously slower to adopt any new technology, aren’t they?
    No similar set of curves for SeaMonkey + Lightning? Or are SeaMonkey users lost in the “purple noise” of the 0% to 1% of “other” in the second graph?

    Best regards,
    Mozilla/5.0 (X11; U; Linux i686; en-US; rv:2.0b2pre) Gecko/20100701 Lightning/1.1a1pre SeaMonkey/2.1a3pre – Build ID: 20100701101320

  4. Tony, you’re correct.
    It is our reading as well, that the lower TB 3.x numbers during the workweek are mostly due to enterprise users, still working with TB2.
    You’re also correct that SeaMonkey users are in the “purple noise” as you call it. SeaMonkey 2.0.x users currently make up for roughly 0.2% of our total user base. Users of SeaMonkey 2.1pre builds are negligible. I’ve prepared a chart of the SM2 numbers for you. You can look at it here:
    Be advised to look at the scale of the Y-axis ;)

  5. Maybe enterprise users have different needs… Me and my users are stuck with Thunderbird 2.x because funambol sync plugin doesn’t work yet with thunderbird 3.x.

  6. I don’t suppose there is anyway to track sunbird usage?
    As far as I’m concerned lightning/sunbird are roughly the same, but I was starting to find the interface with thunderbird a bit awkward, so just changed back to sunbird.

  7. What percentage that does not currently use lightning, would be using it, if you provided a 64 bit build of it?

  8. How are the daily usage statistics gathered? Does the app phone home?

  9. @nemoinis
    Lightning contacts the server once a day (when it is running) to look for updates. Those so-called update pings are counted. This is a well documented behaviour and a security feature, because otherwise we wouldn’t be able to deliver security updates to our users in a fast and efficient way.

  10. Until someone creates a real, functional task list integration with Google tasks, Lightning (in or out of Thunderbird) is a 50% solution. Calendar integration is great, but without Task integration – it’s only half way there. Please do not suggest one of the many work-arounds that require anti-productivity.