Changes up to Thunderbird 91 Beta

Thunderbird 81 Beta

messageDisplay API

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

See the documentation on those functions and events for more information.

Thunderbird 82 Beta

compose API

Attachments can now be specified in the beginNew, beginReply, and beginForward functions.

tabs API

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

messageDisplayScripts API

Content script functions can now 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.

Thunderbird 83 Beta

compose API

ComposeAttachment objects now have a size property with the size of the attachment in bytes.

contacts API

The onUpdated event now calls listeners with a second argument, containing details of the changes made. For example:

{
  "FirstName": {
    "oldValue": "Daniel",
    "newValue": "Danielle"
  },
  "DisplayName": {
    "oldValue": "Daniel Smith",
    "newValue": "Danielle Smith"
  }
}

menus API

A compose_attachment context can now be used. 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.
The standard properties available to onShown are now available for messages being displayed, if your extension has the messagesRead permission.

Thunderbird 84 Beta

compose API

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.

menus API

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

tabs API

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

windows API

The openDefaultBrowser(url) function has been added.

browserAction API

The setLabel(details) and getLabel(details) functions have been added. 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 added. 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 added. 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 85 Beta

addressBooks API & contacts API

The addressBooks API and contacts API will now return read-only address books. Add-ons that may update contacts and address books should check the readOnly flag of AddressBookNode.

accounts API

The composeHtml property has been added 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([includeSubFolders]) 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.

messages API

query([queryInfo]) supports queries for messages with a given headerMessageId

Thunderbird 86 Beta

theme API

The theme API was added to Thunderbird (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.

Thunderbird 87 Beta

commands API

The commands API now supports the internal shortcuts _execute_compose_action and _execute_message_display_action.

Thunderbird 88 Beta

compose API

added a type property to ComposeDetails, to distinguish between new, reply, forward and draft
added a from property to ComposeDetails, to get/set the actual from address (independent of the used identity)

contacts API

fixed quickSearch([parentId], queryInfo) to not fail on mailing lists

menus API

added a tools_menu context to ContextType
added a selectedAccount property to OnShowData and OnClickData, if the menu was opened on a root folder in the folder pane
fixed onClicked to keep the user input status so openPopup([options]) can be used

messages API

added listAttachments(messageId) and getAttachmentFile(messageId, partName) methods to work with message attachments
fixed getRaw(messageId, [options]) to work for nntp/news messages

Thunderbird 89 Beta

mailTabs API

added getCurrent() and get(tabId) functions

menus API

fixed browser_action ContextType
added message_display_action and compose_action ContextType
introducing a fieldId property to OnClickData and OnShowData to to support fields part of the Thunderbird UI (currently supported values are composeSubject, composeTo, composeCc, composeBcc, composeReplyTo and composeNewsgroupTo)

Thunderbird 90 Beta

cloudFile API

added support for the browser_style manifest property to the cloudFile API

compose API

added sendMessage(tabId, [options]) function
added getComposeState(tabId) function
added onComposeStateChanged event
added ComposeState type
added redirect enum to type property of ComposeDetails

messages API

added size property to the MessageHeader

Thunderbird 91 Beta

accounts API

list([includeSubFolders]), get(accountId, [includeSubFolders]) and getDefault([includeSubFolders]) now have an optional parameter includeFolders to specify if the returned MailAccount objects should populate the folders property. Defaults to true

addressbooks API

added remote property to AddressBookNode

cloudFile API

added the tab parameter to onFileDeleted
added the tab parameter to onFileUpload
added the tab parameter to onFileUploadAbort

compose API

all attachment related functions and events now also require the compose permission

contacts API

added remote property to ContactNode
second parameter to quickSearch([parentId], queryInfo) can now be a qeuryInfo object instead of just a string, to define mored detailes query parameters

folders API

delete(folder) now requires the messagesDelete permission
added new function getParentFolders(folder, [includeSubFolders]) to get information about the current hierarchy level and parent folders
added new function getSubFolders(folder, [includeSubFolders]) to get information about subfolders
the create(destination, childName) function can now create folders in the root of an account, by specifying an account instead of a folder as first parameter
added move(source, destination) function
added copy(source, destination) function
added getFolderInfo(folder) function and MailFolderInfo type to obtain additional folder information like totalMessageCounts or unreadMessageCounts
added onCreated event
added onRenamed event
added onMoved event
added onCopied event
added onDeleted event
added onFolderInfoChanged event

identities API

added identities API (including create/delete/update functions and onCreated/onDeleted/onUpdated events)
added signature and signatureIsPlainText to MailIdentity

mailingLists API

added remote property to MailingListNode

mailTabs API

the MailTab object now includes a viewType property, supporting the values ungrouped, groupedByThread and groupedBySortType
the update([tabId], updateProperties) function allows to set the new viewType property

messages API

query([queryInfo]) now searches all messages and not only the indexed ones
added support for negative tag search to query([queryInfo])
added includeSubFolders to search folders recursivly with query([queryInfo])
added onUpdated
added onMoved
added onCopied
added onDeleted
added the messagesDelete permission to guard delete(messageIds, [skipTrash])

tabs API

added type property to Tab, supporting addressBook, calendar, calendarEvent, calendarTask, chat, content, mail, messageCompose, messageDisplay, special and tasks
added type as supported property of the queryInfo parameter of query([queryInfo])