Changes up to Thunderbird 78 ESR

Thunderbird 74 Beta

legacy API

The legacy API has been removed.

accounts API & folders API

The MailFolder object gained a subFolders property. From now on the accounts API functions will return a hierarchy of folders instead of a flat list. If you still need a flat list you should traverse the folder hierarchy:

browser.accounts.list().then(accounts => {
  let arrayOfFolders = [];

  function traverse(folders) {
    if (!folders) {
      return;
    }
    for (let f of folders) {
      arrayOfFolders.push(f);
      traverse(f.subFolders);
    }
  }

  for (let account of accounts) {
    traverse(account.folders);
  }
  return arrayOfFolders;
});

This example code works with both the current API in 68 and the new version in 74 (which will be backported to 68 after some time in beta).

compose API

The compose API gained two new functions and an event. The getComposeDetails and setComposeDetails functions let you retrieve or change the recipients and subject of a message being composed. More details will be added later. The onBeforeSend event is fired when a message is about to be sent. At this point your extension can prevent sending or change the same details as in the new functions.

messages API

The query function can now query by tags.
The MessageHeader object now has junk properties: junkScore is an integer score from 0 (not spam) to 100 (spam). junk shows whether or not that score is greater than the junk threshold.

Thunderbird 75 Beta

action APIs

The onClick event of the action APIs now has information about the active tab and the click event.

This brings the events into line with browser WebExtensions. For messageDisplayAction, this is a change of behavior – previously the ID of the active tab was passed as the first argument.

This change was uplifted to 74 beta 2.

compose API

The onBeforeSend event now has information about the active tab.

This change was uplifted to 74 beta 2.
The compose API functions can now handle the message body.

All responses from getComposeDetails calls and onBeforeSend events now return the message body. How you handle this depends on the composition mode (plain text or HTML). For plain text composition mode, the isPlainText field is set to true and plainTextBody should be used. For HTML composition, isPlainText is set to false and body should be used.

The body field is a string. You should parse this to an HTML document before modifying it, and serialise the document back to a string before calling setComposeDetails. Here’s a sample extension.

messages API

A new event was added: onNewMailReceived.

Your extension can now be notified of incoming mail. This is based on the MailServices.mfn.msgsClassified notification.

Thunderbird 76 Beta

accounts API

Thunderbird 76 introduces the MailIdentity type for interacting with mail identities. Like the rest of the accounts API, it is mostly read-only as we believe that configuration of identities should only happen using the built-in UI.
The MailAccount type now contains a list of identities associated with that account. The default identity is listed first and other identities are in no particular order.
The accounts API now has a setDefaultIdentity(accountId, identityId) function.

compose API

The ComposeDetails type now has an identityId field for getting or setting the identity associated with a message being composed.

mailTabs/messageDisplay

For consistency with other APIs and with browser WebExtensions (ie. those used in Firefox, etc.), some events that passed a numeric tab ID to listeners now pass an object representing the tab instead. This change is not backwards-compatible.

The affected events are:

messages API

The accountsRead permission is now required for all functions that accept a MailFolder argument. The permission was already required to obtain a MailFolder anyway, so this change should not break extensions.

experiment APIs

For extensions with the addressBooks permission, a new addressBookManager object is available to WebExtensions experiment implementations. The addressBookManager provides the following functions to help you interact with the addressBooks API, contacts API and mailingLists API:
- findAddressBookById, findContactById, findMailingListById to help you find “real” address book objects (nsIAbCard, nsIAbDirectory) for the IDs provided by the addressBooks API. Note that there is active development in the address book and these interfaces will be changing in the near term without public announcement.
- convert to turn “real” objects back into API-friendly objects.
For more information on these functions see the source code of the addressBooks APIs.

Thunderbird 77 Beta

compose API

The compose API functions beginNew, beginReply, and beginForward now return a Tab object for use with other API functions.
Listeners to the compose.onBeforeSend event are now called sequentially in the order they were added. Be aware that other extensions may see this event before or after yours does.

tabs API

Events in the tabs API and windows API now fire in many more situations:
- Calendar tabs now fire tabs.onCreated, tabs.onActivated, and tabs.onRemoved just like other tabs do.
- The first 3-pane tab in a main window now fires tabs.onCreated when the window opens.
- Address book, composition, and message display windows now fire tabs.onCreated and tabs.onRemoved events as well as windows.onCreated and windows.onRemoved events. Each of these windows has exactly one tab in the tabs API and the added events reflect that.
  
  Whether the tabs event happens before or after the corresponding windows event is non-deterministic.

composeScripts API

Content script functions can now operate on a compose window “tab” in the same way they do on a content tab in Thunderbird or Firefox. (Despite the fact they don’t have tabs, compose windows have one tab object under the tabs API.) This requires the compose permission.

Here are some basic examples. See the MDN documentation for a more in-depth explanation.

// Where tabId is the id of a compose window tab:

browser.tabs.executeScript(tabId, {
  code: `document.body.textContent = "Hey look, the script ran!";`,
});

browser.tabs.executeScript(tabId, {
  file: "compose.js",
});

browser.tabs.insertCSS(tabId, {
  code: "body { background-color: red; }",
});

browser.tabs.insertCSS(tabId, {
  file: "compose.css",
});

browser.tabs.removeCSS(tabId, {
  code: "body { background-color: red; }",
});

browser.tabs.removeCSS(tabId, {
  file: "compose.css",
});

Scripts can also be registered to run automatically on composition window “tabs”, using the new composeScripts API. Again, this works just like the contentScripts API:

let registeredScripts = await browser.composeScripts.register({
  css: [
    // Any number of code or file objects could be listed here.
    { code: "body { background-color: red; }" },
    { file: "compose.css" },
  ],
  js: [
    // Any number of code or file objects could be listed here.
    { code: `document.body.textContent = "Hey look, the script ran!";` },
    { file: "compose.js" },
  ],
});

Added code will run immediately and CSS will be immediately applied to already-open composition windows, and any new composition windows.

The returned value, registeredScripts in this example, is an object with which you can unregister the code/CSS:

await registeredScripts.unregister();

Warning

This functionality has the ability to completely destroy every message being composed, with no way to undo it. Be careful!

Note

Javascript or CSS applied by these methods is not sent with the message. This is not a way to decorate messages or make them interactive.

Thunderbird 78.0 ESR

compose API

Attachments in the compose window can now be accessed with the compose API. These functions have been added:
These events have been added:
- onAttachmentAdded
- onAttachmentRemoved
See the documentation on those functions and events for more information.
A new event, onIdentityChanged was added.

identity API

The browser.identity namespace for OAuth handling was enabled.

Thunderbird 78.4.0 ESR

compose API

Backported support for attachments being specified in the beginNew, beginReply, and beginForward functions.

messageDisplay API

The getDisplayedMessages(tabId) function has been backported to allow access to details of multiple-selection of email. Previously only a single selection function was available.
The onMessagesDisplayed event has been backported.

messageDisplayScripts API

Backported support for content script functions to operate on a message display tab in the same way they do on a content tab in Thunderbird or Firefox. This requires the new messagesModify permission.

Here are some basic examples. See the MDN documentation for a more in-depth explanation.

// Where tabId is the id of a message display tab:

browser.tabs.executeScript(tabId, {
  code: `document.body.textContent = "Hey look, the script ran!";`,
});

browser.tabs.executeScript(tabId, {
  file: "display.js",
});

browser.tabs.insertCSS(tabId, {
  code: "body { background-color: red; }",
});

browser.tabs.insertCSS(tabId, {
  file: "display.css",
});

browser.tabs.removeCSS(tabId, {
  code: "body { background-color: red; }",
});

browser.tabs.removeCSS(tabId, {
  file: "display.css",
});

Scripts can also be registered to run automatically on messages being displayed, using the new messageDisplayScripts API.

Again, this works just like the contentScripts API:

let registeredScripts = await browser.messageDisplayScripts.register({
  css: [
    // Any number of code or file objects could be listed here.
    { code: "body { background-color: red; }" },
    { file: "display.css" },
  ],
  js: [
    // Any number of code or file objects could be listed here.
    { code: `document.body.textContent = "Hey look, the script ran!";` },
    { file: "display.js" },
  ],
});

Added code will run immediately and CSS will be immediately applied to already-open message display tabs or windows, and any new message display tabs or windows.

The returned value, registeredScripts in this example, is an object with which you can unregister the code/CSS:

await registeredScripts.unregister();

Note

This functionality does not permanently alter messages, only what the user sees when they are displayed.

tabs API

The connect and sendMessage functions now work as they do in Firefox.

Thunderbird 78.5.0 ESR

compose API

ComposeAttachment objects now have a size property with the size of the attachment in bytes.
Backported support for the compose_attachment context. This context applies when the user opens a context menu on selected attachments in a compose window. The selected attachments can be accessed from the attachments property in an onShown or onClicked listener.

tabs API

At start-up, tabs.create will now wait for a window to open before attempting to open a tab.

Thunderbird 78.6.0 ESR

menus API

The standard properties available to onShown are now available for messages being composed, if your extension has the compose permission.

windows API

Backported the openDefaultBrowser(url) function.

Thunderbird 78.6.1 ESR

browserAction API

The setLabel(details) and getLabel(details) functions have been backported. It is now possible to set a label value different from the title (which is used as tooltip text). The label can be set to an empty string to make the action button not have a label at all. If the toolbar is set to text-mode only (no icons), the action button label uses the title as fallback, in case an empty label has been set.

composeAction API

The setLabel(details) and getLabel(details) functions have been backported. It is now possible to set a label value different from the title (which is used as tooltip text). The label can be set to an empty string to make the action button not have a label at all. If the toolbar is set to text-mode only (no icons), the action button label uses the title as fallback, in case an empty label has been set.

messageDisplayAction API

The setLabel(details) and getLabel(details) functions have been backported. It is now possible to set a label value different from the title (which is used as tooltip text). The label can be set to an empty string to make the action button not have a label at all. If the toolbar is set to text-mode only (no icons), the action button label uses the title as fallback, in case an empty label has been set.

Thunderbird 78.7.0 ESR

accounts API

The composeHtml property has been backported to the MailIdentity type, to indicate, if the identity uses HTML as the default compose format.
The getDefaultIdentity(accountId) function has been added, to get the default identity of a given account. Use getDefault([includeFolders]) to get the default account.

compose API

The begin* functions now honor body, plainTextBody and isPlaintext as compose format selectors, overriding the default compose format of the used/default identity. The accounts API can be used to get the used/default identity and its default compose format.
The beginNew function now has an optional messageId argument. If messageId is provided, the referenced message is opened to compose as a new message. This works for ordinary messages and templates.
Using beginForward function with a forwardInline type and details argument specified has been fixed.

Thunderbird 78.7.1 ESR

theme API

The theme API was backported (see bug 1684666). It’s more or less the same as the Firefox theme API, but has been extended to better fit the needs of Thunderbird.

The color key sidebar_highlight_border has been added.