Thunderbird 78 FAQ

This document answers questions for new users of Thunderbird 78, in particular users who have upgraded from a previous version.

Where can I find more information on changes and new features in Thunderbird 78?

Please refer to the following documents:

After upgrading to Thunderbird 78, I cannot receive or send email messages.

One reason why this might happen is when your email provider is using outdated security protocols. Thunderbird takes protecting the privacy and security of your communication serious. That is why, by default, Thunderbird 78 will not connect to servers that do not support the modern TLS 1.2 connection security protocol. So if your email provider only supports the outdated security protocols TLS 1.0 or TLS 1.1, downloading (receiving) and sending emails will not work by default. If you really need to connect to such mail servers with outdated security, or if you want to check if this is the cause of your problem, you can temporarily re-enable the older security protocols in Thunderbird settings.

How to enable outdated security protocols TLS 1.0 and 1.1

  1. Open Config Editor (about:config)
    • > OptionsPreferences > Find in OptionsPreferences
    • In the searchbox, type: about:config, then press Enter.
    • Click on the button Config Editor… in the search result.
  2. In the about:config dialog, search for: security.tls.version.min
  3. Double-click on the found preference security.tls.version.min and change its value to 1, then press Enter.
  4. Restart Thunderbird and try to download your messages.

If you can download your messages after changing this preference:

  • Please inform your email provider to upgrade the security protocols on the server to support TLS 1.2.
  • Revert the preference security.tls.version.min to its original value as soon as possible by repeating the above procedure, then right-click on the preference and choose Reset from the context menu.

If you still have difficulties after trying TLS changes, see:

When writing a new message, how can I add, edit, or remove recipients in Thunderbird 78?

We have redesigned the addressing area for more efficiency, transparency, and convenience. Please find more information in the following documents:

Where can I find information on Thunderbird's new encryption technology, OpenPGP?

For any questions or more information about Thunderbird's new message encryption feature, OpenPGP, please see the following document:

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