New in Thunderbird 52.0

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This version of Thunderbird is no longer supported. Please update your version of Thunderbird to enjoy the latest features.

This article describes the major changes that are visible to users in Thunderbird version 52.0. Full details of all the changes can be found in the Thunderbird 52 release notes.

Compared to Thunderbird version 45.0, it has far less visible changes to the user interface but instead, many long-standing bugs and annoyances were fixed.

Mail composition

The most important change is how images are included in a compose window. Images are now included as data URIs and not as references to parts of other messages or operating system files. This allows better interoperability with office packages such as MS Office or LibreOffice. It also fixes long-standing problems with attaching images from other messages. Images linked from locations on the Internet will no longer be downloaded and attached to the message automatically. This can be changed for each image individually via the Image Properties dialog or globally by setting the preference mail.compose.attach_http_images.

Since data URIs are basically raw binary data displayed in the user interface, these are now shortened in the Image Properties dialog and the Insert HTML dialog, for example:

Image properties TB52

When pasting images that reference operating system files into the compose window, the image will now be blocked and a notification will be displayed:

Blocked image TB52

This is to protect users from inadvertently disclosing files.

Main Message Window - Folder Pane

The folder pane now has a Folder Pane Toolbar on the top which comes preconfigured with the Folder Views switcher. The Folder Pane Toolbar can be enabled through the View menu > Toolbars.

Switcher TB52

Main Window - Thread Pane

The Correspondents column with new icons is now the default for all new folders. There is no forced conversion. This can be switched off with the preference mail.threadpane.use_correspondents.

Correspondents TB52

Calendar - Lightning - Event in a Tab

Events can now be created and edited in a tab. To enable this option, select Edit events and tasks in a tab instead of in a dialog window in the ToolsEditThunderbird menu > OptionsPreferences > Calendar > General tab.

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