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Upgrading to Thunderbird version 60

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1347 Words
17:00 | by Alex Vie in Site
Reading time: approx. 5 minute(s).

Mozilla Thunderbird has been my e-mail client and PIM of choice for many years on various operating systems, including Windows, Linux and FreeBSD. It has been a reliable piece of software, generally doing what it’s supposed to do and causing little problems. Once, many years ago, Thunderbird was a first class citizen for the Mozilla Foundation and got the same amount of attention as the Foundation’s flagship product, Firefox. In recent years however, the development pace has slowed down considerably due to lack of manpower and maybe lack of direction, resulting in a piece of software that only got minor refinements instead of major new features and overhauls. Since Thunderbird has always been fairly feature-rich, this is not really a problem. Apart from maybe MS Outlook, it can still be considered the most flexible and feature-complete e-mail client for desktop operating systems.

Extension woes

Like its big brother, the web browser Firefox with which it shares a large part of its code base, Thunderbird supports extensions, a feature that allows the user to tailor the application to one’s personal needs by adding new features or changing existing ones. At the same time, the ability to use extensions has been the source for many issues and frustration in the history of Firefox and Thunderbird. With every major upgrade, extension compatibility became a problem, because the extension API was never stable across major versions. As a result, extensions needed to be maintained and updated for new major releases, often sacrificing backwards compatibility, while unmaintained extensions frequently stopped working with a new Thunderbird release.

Version 60 new things

Version 60 will be the next major release with long term support, which means it will be the direct successor of version 52, the current one which was released over a year ago. The versions 53-59 were development versions not meant to be used by end users. As of writing this article, the 8th (and presumably last) beta version of Thunderbird 60 is the most recent one and from what I’ve heard, the final will be out soon, likely unchanged from this beta.

Thunderbird 52.x with my userChrome modifications
Thunderbird 52.x with my userChrome modifications
Thunderbird 52.x with my userChrome modifications
Thunderbird 60 screenshot
Thunderbird 60 screenshot
Thunderbird 60 screenshot

The screenshots above show Thunderbird 60 (left) and the older version 52 (right) side-by-side. Both are using the same userChrome.css modifications with the default theme. As you can see, the differences are marginal at best, the major new thing is the new icon set that provides a better contrast and a slightly modified theme that blends well with the trend of minimalist and flat operating system themes.

The following screen shot below shows Thunderbird 60 without any UI customization at all. The new theme, taken from Firefox „Quantum” with square tabs and completely flat tool bars is clearly visible and gone are the curved tabs that were introduced with the Australis UI redesign a couple of years ago.

Thunderbird 60 default without any customisation
Thunderbird 60 default without any customisation
Thunderbird 60 default without any customisation

Extension compatibility

Like Firefox Quantum, Thunderbird supports the new web extensions API. This basically means that all old (so-called legacy extensions) extensions that were written for the old API would stop working in Thunderbird 60 with a complete rewrite of the extension as the only solution to the problem. Since the Thunderbird extension ecosystem suffers from very little active development and therefore contains many unmaintained projects, this compatibility problem could have a potentially catastrophic impact on Thunderbird, because many users would probably stop using TB should essential add-ons no longer be available.

Fortunately, there is a solution to the problem. Thunderbird 60 supports old extensions, but this feature must be enabled. So the first thing after upgrading you should do is to open the configuration editor and change the following setting to false.


You can find the configuration editor on the Advanced page of the options dialog. Click on the Config editor button and use the search box in the dialog to find the setting. After changing the setting, Thunderbird must be restarted. With that setting active, most extensions that were compatible with Thunderbird 52 should work with version 60. A few (one example would be the Google Calendar connector) still require an update.

I’am not an extension nut, so the number of add-ons I use is fairly limited, but here is the list of my extensions and all of them are, in fact, working on TB 60.

  • Dorando keyconfig
  • Provider for Google Calendar (required an update)
  • Quick Filter Watched Threads (simply adds a toolbar button on the filter bar)
  • Signature switch
  • Smart Template4

Like mentioned above, only the Calendar Provider needed some attention to obtain and install the manual update which has not yet been released. I assume, this extension update will be available when Thunderbird 60 reaches final release status, which should be by the end of June.

Other observations

First, before updating backup your profile. This is mandatory, because backwards compatibility is not always guaranteed. Essentially this means, there is a possibility that after upgrading to Thunderbird 60 your profile might become incompatible with older versions, so you would not be able to go back to TB 52, should you feel the need for such a step in case of too many problems or other issues. Best practice is to follow this guide which explains how to find and backup your Thunderbird profile on Windows.

With my relatively short list of extensions (see above), I did not run into troubles at all. The upgrade went smooth, with one exception: I had to obtain a beta version of the Google Calendar Provider to make Lightning work again with my Google Calendar. If you have troubles finding it, here is a link to the XPI.

Noteworthy improvements

  • When composing a message, it’s now easy to toggle the attachment bar by using the Alt-M keyboard shortcut at any time.

  • It is now possible to compact IMAP folders while the account is connected.

  • Existing accounts / folders can be converted from MBOX to Maildir format (and presumably vice versa even though that does not make much sense). The Maildir format stores messages in one file per message and is more robust than MBOX which stores all messages in a single large file. Be warned though, the conversion from MBOX to Maildir can take a lot of time and my Thunderbird was consuming insane amounts of memory (up to 2.5gig) while doing the conversion of my INBOX.

  • The Calendar add-on (Lightning) was improved considerably with new features to handle invitations and notifications for collaborative events better.

  • A dark theme is available.

  • The EFAIL problem, what affected practically all ways to send encrypted mail, has been fixed completely

On top of this, many smaller issues have been fixed. Overall, TB 60 also feels faster, more responsive and seemingly uses less memory than TB 52. It also appears to be stable, none of the 3 beta versions I’ve been testing over the last couple of weeks, crashed even once.

So, is an upgrade advisable?

I would say, yes, absolutely. The EFAIL fix alone is worth the upgrade, particularly for users who do need encryption or digital signatures. The extension apocalypse can be mitigated by using the method described above, so most extensions should continue to work, but as it always has been with Thunderbird, there is no guarantee. Some add-on may simply refuse to work and if you’re unlucky, it’s one of the many unmaintained ones. Overall, the relatively new features might appear meager, but they do add some value to Thunderbird and some of the improvements to existing features round out the package. A modernized and arguably more attractive user interface is something that is always welcome among users and gives Thunderbird a fresh new look. {:dc} {:cols}