Thunderbird Release Notes

Check out what’s new, the known issues and frequently asked questions about the latest version of Thunderbird. As always, you’re encouraged to tell us what you think, or file a bug in Bugzilla.

What's New in Thunderbird

The latest version of Thunderbird has the following changes:

Several fixes to improve stability.
Fix a security issue, see the Security Advisory.

You may also be interested in the Thunderbird 10.0 release notes

System Requirements

Before installing, make sure your computer meets the system requirements.

Downloading

Mozilla provides Thunderbird for Windows, Linux, and Mac OS X in a variety of languages. You can get the latest version of Thunderbird here.

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

Installing

Please note that installing a new version of Thunderbird will overwrite your existing installation of Thunderbird. For all systems, you won't lose any of your messages or address books, but some of your extensions and other add-ons might not work until they are updated by the author.

Uninstalling

You can remove Thunderbird through the Control Panel in the Start Menu on Windows, by removing the Thunderbird application on OS X, or by removing the thunderbird folder on Linux.

Removing Thunderbird won't remove your emails or newsgroup messages. This data is stored in your profile folder, which is located in one of the following locations depending on your operating system:

Windows Vista	Users\<UserName>\AppData\Roaming\Thunderbird
Windows 2000, XP, Server 2003	Documents and Settings\<UserName>\Application Data\Thunderbird
Mac OS X	~/Library/Thunderbird
Linux and Unix systems	~/.thunderbird

Any version of Thunderbird that you install after removing Thunderbird will continue to use the data from this profile folder.

Extensions and Themes

Extensions installed under previous versions of Thunderbird may be incompatible and/or require updates to work with Thunderbird. Please report any issues to the maintainer of the extension.

When you install Thunderbird all of your Extensions and Themes will be disabled until Thunderbird determines that either a) they are compatible with this release or b) there are newer versions available that are compatible.

Known Issues

This list covers some of the known problems with Thunderbird. Please read this before reporting any new bugs.

All Systems

Thunderbird 10 may stop working with some mail and LDAP servers that are incompatible with the way Thunderbird prevents CBC-related attacks on TLS 1.0 and SSL 3.0. Contact the server vendor for a fix. We have heard of issues with these servers:
- Kerio Connect - we are working with the vendor to resolve the issue. See Bug 723551 for more information
- Merak Icewarp - we are working with the vendor to resolve the issue. A possible work around has been provided, see Bug 723109 for more information
If you are unable to view content for your RSS feeds in the Wide View Layout, you may need to disable the Lightning Calendar add-on if you have it installed or switch to Classic View and restart Thunderbird. (Bug 531397)

Troubleshooting

Poorly designed or incompatible extensions can cause problems with your email client, including make it crash, slow down message display, etc. If you encounter strange problems relating to parts of the email client no longer working, the email client not starting, windows with strange or distorted appearance, degraded performance, etc, you may be suffering from Extension or Theme trouble.
Restart the email client in Safe Mode - select Help followed by Restart with Add-ons disabled. When started in Safe Mode all extensions are disabled and the Default theme is used. Disable the Extension/Theme that is causing trouble and then start normally.
If you encounter strange problems relating to email, feeds or newsgroup messages, it is recommended that you try creating a new profile and attempting to reproduce the problem before filing bugs. Create a new profile by running Thunderbird with the -P command line argument, choose the "Manage Profiles" button and then choose "Create Profile...". Migrate your settings files (Emails, feeds, etc) over one by one, checking each time to see if the problems resurface. If you do find a particular profile data file is causing a problem, file a bug and attach the file, being sure to remove any private information as necessary.

Frequently Asked Questions

What can I do to help?
Your feedback is essential to the project and makes Thunderbird better with every release. Give us your feedback on Thunderbird at our GetSatisfaction site. Please read these notes and the bug filing instructions before reporting any bugs to Bugzilla.
Where can I discuss Thunderbird features or issues?
If you want to join the conversations about new features or need troubleshooting advice, visit Get Satisfaction. You can also post questions in the "mozilla.support.thunderbird" newsgroup, available on Mozilla's news server, or via the web, using Google Groups. It is also available as a mailing list. Please read the Mozilla Forum Etiquette page before posting.
Where can I get extensions and themes (add-ons)?
Extensions and Themes can be downloaded from Thunderbird Add-ons.
Who makes Thunderbird?
Lots of people. See Help->About Mozilla Thunderbird, and click the "global community" for a list of some of the people who have contributed to Thunderbird.
Where's the Thunderbird source code?
A tarball of the Thunderbird source code is available for download. The latest development code can be obtained by Mercurial. For more details on the layout of the source, see the comm-central information page. Please follow the build instructions.

Contributed Builds

These are unofficial builds and may be configured differently than the official Mozilla builds. They mas also be optimized and/or tested for specific platforms. You can browse through the available contributed builds on the FTP site.