Mozilla Release Notes

Version 154.0, first offered to Release channel users on August 18, 2026

New

Firefox's Local Network Access protections now extend to WebSocket connections. Websites that try to open a WebSocket to a device on the local network will now ask for permission first.

In Smart Window, Firefox can now suggest groups of related tabs and propose a name for each group.

This feature is part of a progressive roll out.

Firefox on Windows is now a supported browser for NVIDIA GeForce NOW, letting users stream supported PC games directly in the browser.

Local Firefox profile backups are now available on macOS in addition to Windows and Linux, and backups can be restored across all three platforms.

Sites can now be exempted from having their cookies and site data cleared on shutdown without also being exempted from tracking protection and other cookie restrictions.

The full-page Translations feature now translates <iframe> content.

The full-page Translations feature now runs language identification on all page loads, resulting in an improved experience for offering translations to users.

Windows users can now choose a different Firefox app icon in Settings. This is not yet available for MSIX installations, macOS, or Linux, but is coming soon.

The address bar now includes a Manage AI quick action that opens the AI controls in Settings.

Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.

Fixed

Fixed an issue on macOS where closing a browser window could leave behind an invisible window that continued to capture mouse clicks over the area where it used to be.

Fixed an issue on Windows where an auto-hiding taskbar would not appear until the Firefox window had been minimized and restored after launch.

Fixed an issue where the Windows taskbar would appear in front of a full screen Picture-in-Picture window.

Fixed the Vertical Tabs sidebar staying visible in full screen mode. It now hides along with the toolbars and reappears when the cursor moves to the edge of the screen.

Fixed PDF documents not being scaled correctly in print preview when the Fit to Page Width option is used.

Various security fixes.

Changed

Video seeking is now significantly faster on all operating systems, making it quicker to jump to a point in a video.

Text selected in a PDF is now highlighted the same way as text on a web page, and the highlight color follows operating system settings such as high-contrast mode.

Firefox View is moving out of the toolbar by default for new profiles and for profiles where it hasn't been used recently. It can still be opened from List all tabs > View all tabs, or added back from the Customize toolbar menu.

Enterprise

You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 154 Release Notes.

Developer

The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.

Web Platform

Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties control the leading space above and below text, enabling simpler and more consistent vertical spacing and alignment.

Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.

Added a time picker user interface to <input type="time"> and <input type="datetime-local">, making selecting a time more accessible and intuitive.

Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.

Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.

Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Firefox now supports the Iterator.prototype.join method, which allows joining an iterator into a string, similar to Array.prototype.join.

Community Contributions

With the release of Firefox 154, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 32 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

Ale Camara [:ale]: 2054573
andra: 2022992, 2046118
andrea.distefano: 1470011
Anil Verman: 2040057
Benoit: 2047559, 2049316, 2050403
Brieuc Gommard: 2031346, 2049309
christopher.staite: 2037813
conor: 1988166
Cornelius | CE student: 2046119
Devin Rousso: 2052932
Diego: 2018728
elvyria: 2027522
Gabe: 2049141
Hagen: 2049264
Hillwood Yang: 2048250
Jaimukund Bhan: 2034642
Kafji: 2051493
Kometes: 1954212
Luiz Henrique Vieira: 2050546
Majed El-Barbari: 2040240
Marcelo Camargo: 2009295
Mayank Bansal: 2055744
muhammad shaikh: 2016932
Raimund Hook: 2050794
Rebekah: 2052857
Riza: 2044167
Ronak Sheth: 2048099
taylor: 1419649
Tim McNulty: 2052560
Yogeshdangal66: 2031348
Zehui Xu: 2028402
占旭哲: 1992363

Original source

What’s New

Preview functionality for attachments on macOS

CMS message with AuthEnvelopedData can be decrypted properly in Thunderbird

Global search results can open in list view by default with new setting

"Copy To" folder context menu added for message/rfc822 attachments

Optional system tray mode that hides Thunderbird when the last window closes

Support for dragging message/rfc822 type MIME attachments to folder tree

Microsoft Graph enabled for Microsoft 365

Fixed

Remote content warnings appeared despite sender block exceptions being applied

Collapsed saved-search folders did not deselect their subfolders

Server-designated special folder flags could be removed until restart

Messages could render excessive trailing blank lines

Copying a message subject included the "Subject:" label in copied text

Moving IMAP folders to Local Folders could delete messages after copy failures

7-bit clean unobtrusive signature payloads were unnecessarily base64 encoded

DisablePasswordReveal policy failed to prevent revealing saved passwords

Account setup tried local-part usernames before full email addresses

Read-only CardDAV address books were incorrectly treated as writable

Autoscroll icon was missing directional arrows in scrollable messages

Blank 1970-dated messages could appear from incomplete message file copies

Opening drafts or templates with invalid quoted-printable data could crash Thunderbird

Thunderbird could crash when inserting a message header into database cache

IMAP repeatedly notified for messages already read on another device

Dragging EWS search folders to Trash caused Thunderbird to crash

Folder compaction displayed incorrect disk space recovery estimates

Custom OAuth settings for EWS account overwrote original account's settings

Thunderbird could crash when going offline with an active IMAP IDLE connection

Thunderbird could crash while running online mail search

Exchange accounts could show repeated false login failures during authentication

Expired newsgroup articles showed an insecure "click here" purge link

IMAP attachments appeared empty after messages were moved by filters

Default special-folder names could reference nonexistent server folders

Thunderbird macOS fell back to Software WebRender after GPU process launch failures

New RSS subscriptions used updated dates instead of published dates

Calendar sort order was not preserved across Thunderbird restarts

"All calendars are disabled" banner reappeared after enabling a calendar

Dismissed CalDAV reminders could permanently stop future event notifications

Read-only CardDAV calendars were incorrectly treated as writable

CalDAV sync failed when server responses used UTF-16 encoding

Visual and UX improvements

Security fixes

As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla

Original source

Version 153.0.3, first offered to Release channel users on August 4, 2026

New

Smart Window includes several enhancements:

• The suggestion list now shows more results, making it easier to find history and switch to open tabs. (Bug 2019042)
• The assistant can now answer questions directly using web search results from Exa, instead of handing off to a search engine. (Bug 2046183, Bug 2044385)

This feature is part of a progressive roll out.

Fixed

Fixed audio and video failing to play, or hanging when seeking, on websites that load media from a Blob URL. (Bug 2056444)

Fixed Internet shortcuts dragged from Firefox to the desktop being marked as untrusted on Windows, which caused a security warning every time they were opened. (Bug 2056865)

Fixed the Bookmarks, History, and other sidebars failing to open when the sidebar is hidden and the password manager has been turned off by an enterprise policy. (Bug 2056857)

Fixed a Mozilla VPN upgrade offer appearing for people in regions where Mozilla VPN is not sold. (Bug 2058264)

Fixed frequent Inspector crashes in the Developer Tools on pages where an extension content script had added event listeners. (Bug 2042101)

Fixed a rare case on Windows where starting Firefox while a partial update was still being applied could leave the installation broken and unable to start. (Bug 2058197, Bug 2058594)

Reference link to 153.0.1 release notes.

Original source

Version 153.0.1, first offered to Release channel users on July 28, 2026

Fixed

• Addressed a startup crash on Windows that could occur after updating Firefox, when some of the application's internal files could not be loaded. Firefox should now start in these cases, although parts of the interface may not display correctly until a further update completes (Bug 2056926).
• Fixed audio playing silently on some music and audio streaming sites after pausing and resuming playback (Bug 2053586).
• Fixed the New Tab page background flashing a few seconds after the page loaded when a custom wallpaper was in use (Bug 2056650).
• Fixed a crash that could occur when a page loaded a frame using a javascript: address (Bug 2054485).
• Fixed a crash that could occur while typing text in an editable area of a page (Bug 2053867).
• Fixed a search engine you had already installed yourself being labeled as "New" when Firefox later started offering the same engine (Bug 2053710).
• Improved pointer lock, used by games and other immersive web content, so that the mouse pointer is less likely to escape the Firefox window (Bug 1255338, Bug 2040628).
• Fixed an issue in the Inspector's Rules view where pseudo-elements could only be expanded once per selected element (Bug 2054525).
• Fixed View Page Source failing to load blob: documents (Bug 2054428).
• Fixed View Page Source timing out on documents that inherit their origin, such as frames using the srcdoc attribute (Bug 2054487).

Reference link to 153.0 release notes.

Unresolved

• Some Windows users may experience a crash on startup after updating, caused by an incomplete update leaving the Firefox installation in an inconsistent state (Bug 1681745). If you are affected, downloading Firefox from firefox.com and installing it over your existing installation will repair it. Your bookmarks, passwords and other data are stored separately and will not be affected.

Original source

Version 153.0, first offered to Release channel users on July 21, 2026

New

High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.

Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.

Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials.

It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.

It is now possible to add images as new pages within PDFs using the Firefox PDF editor.

Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.

Added support for Apple's system-wide full-screen keyboard command (Globe-F).

Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.

Added improved support for videos with overlays so users can more easily access video actions from context menus.

Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Smart Window:

• See and choose AI models directly from the Smart Window assistant.
• New Tab now includes a familiar address bar for typing websites and searching the web.

This feature is part of a progressive roll out.

Firefox Labs

Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.

Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Fixed

Various security fixes.

Changed

Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".

Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.

Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Enterprise

You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 153 Release Notes.

Developer

Developer Information

A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:

• Rules with non-zero width / height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.

The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.

Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.

The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.

The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.

Developers can now use the text import attribute to import text files using the module system.

The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.

The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.

The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

HTTP Compression Dictionaries is enabled via rollout in 153, it will be made permanent in a future release. This can greatly reduce network traffic size for sites that use it.

This feature is part of a progressive roll out.

Community Contributions

With the release of Firefox 153, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 15 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

• Alan Liu: 2009570
• Dineth De SIlva: 2042443
• Freya Arbjerg [:freyacodes]: 2036767
• Garbee: 2045887
• Jessica Foley: 2041062
• John ARNZEN: 2046279
• Max Emig [:maxe]: 230112
• metamuffin: 2045549
• mtan: 2039500
• ozcoder: 2020186
• Pedram Yektamaram: 2042437, 2042440, 2042441, 2042442
• Peter Lafreniere [:n8pjl]: 2041463
• Phone Khant Kyaw Swa: 2008877
• pullmana8: 2031735
• Ryan McCartney: 2039853

Original source

What’s New

Unified folders now display account color indicator with account name tooltip

OAuth login for mail accounts now opens in default web browser

Thundermail services can now be used without installing an add-on

OAuth responses now verify issuer fields and reject missing required issuers

Changed

Removed Odnoklassniki chat setup and directed users to XMPP configuration

Fixed

Ctrl+S did not save PDF attachments opened in Thunderbird tabs

TLS errors incorrectly reported all unknown failures as untrusted certificates

Thunderbird could crash during shutdown

Thunderbird could crash when copying an empty list of messages

New mail alerts incorrectly sized or positioned on some multi-monitor setups

Old IMAP profile migration deleted INBOX and other mailbox files

Space bar did not scroll in PDF attachments opened from emails

'Search Messages' shortcut (Ctrl+Shift+F) failed in standalone message window

Folder location widget used non-localised name

Empty confirmation dialog when more messages opened in tabs than mailnews.open_tab_warning

Removing tags from IMAP messages could fail and tags reappeared after refresh

Folder pane could not be horizontally resized in additional 3-pane tabs

Global search failed to display inaccessible messages found in local folders

Numeric subfolders were sorted alphabetically instead of naturally

Virtual folder folder-picker showed unlabeled IM account as selectable folder

Virtual folders failed to preserve the online search setting

Apple Mail OpenPGP emails failed to decrypt due to hidden recipient key ID

OpenPGP import of public key with experimental packets failed with unclear error

Performance issue when decrypting encrypted messages

Opening messages with OpenPGP keys was slow and blocked the UI for large keyrings

OpenPGP key refresh failed when fingerprint lookup returned multiple results

Invalid S/MIME encryption certificate caused misleading send errors

Esc cleared quick filter pin after changing folder

Dragging email address between compose windows failed to add recipients

Thunderbird could crash when using Find and Replace All

Sending Message dialog got stuck on "Filter complete." after successful send

Compose with PDF attachments opened PDFs instead of creating a new email

Attachments opened via -compose on Windows could use incorrect filenames

Ctrl+Enter opened attachment instead of sending the message

Compose window remained open when delayed sending was enabled

Account hub showed connection security instead of actual authentication method

Account Hub GSSAPI autoconfiguration incorrectly prompted for a password

New identity dialog lacked reply-matching and end-to-end encryption settings

Account Hub manual EWS setup lacked OAuth authentication option

Thunderbird could fail to shut down cleanly during active OAuth requests

Account Hub kept OAuth selected after changing to hostname without OAuth support

Account Hub showed a false error when returning from EWS manual configuration

Account Hub autodetect wrongly prompted for a password when auth was unavailable

QR exports with SMTP passwords generated invalid data for Thunderbird for Android

Message Filters 'Run Now' button remained disabled after filter run or mail check

Redirected CardDAV URLs resolved relative URLs against the wrong host

Thunderbird could crash when completing folder copy/move

Forwarding some Apple Mail messages incorrectly attached inline text as a file

Auto-compaction could corrupt database and cause crashes during syncs

NNTP server with invalid TLS certificate could not be added to certificate exceptions

Sent message in EWS account showed message as unread in the sent items folder

EWS NTLM authentication triggered login failures despite successful syncs

Saving inline Exchange images used incorrect filenames and file types

Cancelled message send could not be retried and hung with SMTP timeout errors

EWS folders failed to show new mail notifications until the folder was selected

Corrupted NNTP account data caused excessive memory use and startup crash

Multiple selected IMAP folders could not be moved or deleted together

Non-Latin IMAP keywords were lowercased and encoded incorrectly as MUTF-7

Message tags were lost when moving folder from local folder to IMAP folder

Reply All button was missing for some EWS messages with multiple recipients

EWS users could not permanently delete individual Trash messages

Removing a chat account threw an exception and failed to clear the UI

Primary Password policy was detected but not enforced for saved account passwords

Copying one recurring event occurrence failed to set the date when pasted

Calendar invites were incorrectly marked processed after calendar sync completed

ICS event comments were not displayed in Thunderbird event details

Visual and UX improvements

Security fixes

As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla

Original source

Version 152.0.6, first offered to Release channel users on July 14, 2026

New

Smart Window includes several enhancements:

• Select text on a page and get quick access to summarize, explain, and more using the built-in assistant. (Bug 2034921)
• Added a row of shortcuts to New Tab, making it easier to get back to sites. (Bug 2048338)

This feature is part of a progressive roll out.

Fixed

Fixed an issue that prevented email tracking protection from being disabled in the redesigned Firefox Settings. (Bug 2049331)
Fixed a hang that could occur after using a file picker dialog on macOS 26. (Bug 2053177)
Fixed the homepage not loading for some enterprise configurations that set it using a legacy autoconfig format. (Bug 2047962)
Various security fixes.

Reference link to 152.0.5 release notes.

Original source

What’s New

Visual signatures can be added to PDF attachments opened in Thunderbird

'Copy Message Link' and 'Copy News Link' added to header pane 'More actions'

Accessiblity is improved in various tree views

Added 'Archive' action to mail notifications

Add "Show Full Path" folder pane option for compact view modes

Unified folders now display account color indicator with account name tooltip

Folder copy enabled within mail server accounts and local folders

'Reset Folder Order' option added to folder pane to reset custom folder sorting

Add `mail.useLocalizedFolderNames' to toggle special folder name localization

'Favorites' added as destination for 'Move To' and 'File' buttons

Added Proton Mail key server and WKD key discovery for Proton domains

Composer now shows a warning if user's configured OpenPGP key expires soon

Enabled configuration of preferred OpenPGP keyserver via the UI

Add mail.openpgp.load_untested_gpgme_version to load untested GPGME version

Added support for generating Unobtrusive Signatures (OpenPGP)

Implemented option to show only messages without any tag

Message body search enabled for OpenPGP and S/MIME encrypted messages

SecurityDevices enabled in enterprise policies

Enable support for DNS over HTTPS

OAuth login for mail accounts now opens in default web browser

Thundermail services can now be used without installing an add-on

OAuth responses now verify issuer fields and reject missing required issuers

Enable the "Sign in with Thundermail" button in Account Hub

Account hub is opened on the first run of Thunderbird

Account Hub email manual config option added

Enable Thundermail OAuth sign-in with account auto-configuration

One-click account setup for Thundermail accounts

Address book cards can be copied to the clipboard as vCard

Enable exporting selected address book cards

Custom Accent Color can be chosen in Appearance Settings

Enable support for Microsoft Exchange via Exchange Web Services

Calendar month/multiweek views are now scrollable with touch screen

Tasks can be sorted by created or modified date

PDF pages can be reorganized directly in the PDF viewer

Changed

'Copy Message Location' removed from mail context menu

Read folders are now removed from Unread Folders view

Special folders are now localized based on a restricted set of names

OpenPGP public key no longer attached by default in signed-only messages

Address books are now created in Account Hub

Yahoo, AT&T, AOL accounts migrated to OAuth 2.0 with PKCE for improved security

GMail OAuth updated to use PKCE

Skype has been retired and therefore dropped from Address book IM selection

Removed pref default_supports_diskspace.{HOST}

Removed pref default_offline_support_level.{HOST}

Removed Odnoklassniki chat setup and directed users to XMPP configuration

Use of the string "Junk" has been replaced with "Spam"

Updated about:rights to replace local with hosted url

Stop shipping 32-bit Linux x86 binaries

'Hide completed tasks' now also hides cancelled tasks

Fixed

Thunderbird could crash when parsing message state

The English string for the Angry emoji was incorrectly named as the Yell emoji

Notification sounds did not respect operating system's do-not-disturb mode

Non-English localized Thunderbird created English special folders on first start

Copying text from some error alerts was not possible

Fastmail CalDAV app password access failed due to forced OAuth regression

Thunderbird could crash in server subscription logic

Could not distinguish folders with same name in 'Recent Destinations' and 'Favorites'

Donation banner stole focus when Thunderbird was running in the background

Unknown command-line arguments passed to Thunderbird did not print warning

Thunderbird could crash when processing new incoming messages

Spam messages triggered new mail notifications before being moved to Spam folder

Web pages with bad certificates displayed as blank

Memory leak after opening New Window from folder pane context menu

Importing a vCard only displayed VCF files in the file picker

Calendar view tabs were not properly keyboard accessible

Ctrl+S did not save PDF attachments opened in Thunderbird tabs

TLS errors incorrectly reported all unknown failures as untrusted certificates

Thunderbird could crash when copying an empty list of messages

Incorrect roaming data directory caused regression on Windows and macOS

Changing to new drafts folder and then back did not correctly restore the folder

Message headers were re-downloaded at every startup

Old IMAP profile migration deleted INBOX and other mailbox files

'Search Messages...' dialog could not be opened outside the email tab

Option did not exist to create new address book under File -> New

Newly created folder was missing under "Recent" when moving a message

Could not compose new message if the folder pane was empty

'Delete' was missing from context menu when multiple IMAP folders were selected

Compacting multiple folders failed and did not compact

Shift-click for 'Edit' button in drafts header view did not work

"Replace All" in Compose did not update plain text until dialog closed

Status bar messages displayed unlocalized folder names or IMAP mailbox names

Saved email filenames were not not always cross-platform safe

Space bar did not scroll in PDF attachments opened from emails

Folder location widget used non-localised name

Empty confirmation dialog when more messages opened in tabs than mailnews.open_tab_warning

Removing tags from IMAP messages could fail and tags reappeared after refresh

Toggling dark message mode did not restore focus and scroll position

'Show remote content' did not display remote content for EML message

Emoji sequences were not properly handled in subject lines

'Delete' button in unified toolbar could delete attachments instead of message

"Repair text encoding" could duplicate recipient and attachments

Some IMAP emails showed current time instead of correct received date

Deleting a single message in folder using 'Group by Sort' failed after CTRL+A

New newsgroups were not added in alphabetical order by default

Sorting by threads only brought threads with unread top messages to the top

News message marked read after NNTP error prevented retrieval from server

'Recent destinations' submenu was not sorted by time of modification

Account column could display incorrect account name

'Tag' submenu of mail context menu could be populated incorrectly

Unified archive subfolders could show wrong names and no messages

Moving saved search/virtual folder under IMAP could fail

New Folder dialog allowed invalid folder creation without a selected parent folder

New/unread messages in collapsed thread were not obvious enough

Pressing Delete on Trash folder could remove it without confirmation

Renaming of a 'unified folder' created a duplicate

Clicking on a folder in the folder pane did not always open folder

Messages nested deeper than 255 levels disappeared from threading view

Performing Delete followed by Undo on thread parent message could corrupt view

Single messages still appeared collapsible after thread members were deleted

Updated threads remained misordered until folder refresh or resort

Global search failed to display inaccessible messages found in local folders

Numeric subfolders were sorted alphabetically instead of naturally

Virtual folder folder-picker showed unlabeled IM account as selectable folder

Some folders showed new mail count prior to receiving mail

Menu Bar -> View contained duplicate accelerator keys

Unified toolbar Spam button did not switch to "Not Spam" when spam message selected

Warning was not logged if mail.openpgp.alias_rules_file file did not exist

Not all headers were signed when creating digitally signed OpenPGP email

When configuring external GnuPG, user was not promted to import public key

"Open and Show" for OpenPGP-signed message (.eml) did not work

Invalidly signed unencrypted emails were indicated as worse than unsigned ones

Reason for revoked certificate was not shown

Apple Mail OpenPGP emails failed to decrypt due to hidden recipient key ID

OpenPGP import of public key with experimental packets failed with unclear error

Opening messages with OpenPGP keys was slow and blocked the UI for large keyrings

OpenPGP key refresh failed when fingerprint lookup returned multiple results

Encrypted Gmail CSE emails with outer opaque S/MIME were not readable

Invalid S/MIME encryption certificate caused misleading send errors

"Search Messages" search did not finish due to unparsable local folders

Search results showed older irrelevant emails before newer exact matches

Filter search on Body missed draft messages containing German umlauts

Esc cleared quick filter pin after changing folder

Thunderbird could crash during local message search

Replying could fail with mailnews.reply_quoting_selection.multi_word set false

Drag-drop of unselected contact inserted wrong or no email address

Changing identity in compose window caused modified draft not to be saved

Shift-click 'Compose Message To' on 'mailto' link did not open in plain text

Reply with selected text lost formatting for HTML messages containing </pre>

Multipart/related attachments were not preserved when editing or forwarding

Forwarded malformed MIME email had empty body and extra attachment

Message compose window was removed from Task Bar after saving as draft or template

Dragging email address between compose windows failed to add recipients

Thunderbird could crash when using Find and Replace All

Multiple saves while using 'Options' -> 'Send a Copy' resulted in multiple copies

Search for "Attachment" in Settings menu did not find "Files and Attachments"

Add-on account creation did not work with Account Hub

Owl install did not show link to website in Account Hub

Username field did not appear in Account Hub when exchange authentication failed

Account Hub advanced config setup did not include default outgoing config

Disabled inputs could be toggled in Account Hub address book

Users could not disable spinning overlay in Account Hub for email

Account Hub local address book creation could continue with blank name

Account Hub email success messages were not always accurate about config source

Calendar/address book sections were shown in Account Hub when there were none

New password-based Exchange accounts failed to save passwords in login manager

Account hub showed connection security instead of actual authentication method

New identity dialog lacked reply-matching and end-to-end encryption settings

Thunderbird could fail to shut down cleanly during active OAuth requests

Account Hub kept OAuth selected after changing to hostname without OAuth support

Account Hub autodetect wrongly prompted for a password when auth was unavailable

Interrupted external OAuth2 setup required restarting Thunderbird

The default account could be reset after restart if uninitialized

Virtual folders did not update correctly for filtered POP3 messages

'Copy Message to' action in a newsgroup filter did not work

Thunderbird could crash while importing mail thread

Thunderbird did not clearly fail when importing profile from a bad source

Thunderbird could not import profile located at the top level of zip file

'Any Number' was unavailable in address book search with 'Match all of the following'

Contact not found in Advanced Address Book Search if phone number had a period

Thunderbird did not display contact photos in WebP format from CardDAV servers

Opening a vCard (.vcf) from file manager or CLI did not work in some cases

Redirected CardDAV URLs resolved relative URLs against the wrong host

Installations from Microsoft Store did not open when clicking 'mailto:' links

Windows new message notification click did not bring Thunderbird to foreground

Microsoft Store installs did not open when clicking 'news://' link or .eml file

Using thunderbird -compose with double quotes made last email address invalid

Clicking the backspace icon in the quick filter field cleared the input field

Subfolder kept stale accessibility unread count after unread messages were deleted

Moving virtual folder within maildir based IMAP or local folder could fail

Thunderbird could crash when completing folder copy/move

'Edit as New Message' and inline 'Forward' not possible with PGP-signed messages

Various MIME improvements

Forwarding some Apple Mail messages incorrectly attached inline text as a file

Thunderbird could crash when marking all messages as read

Auto-compaction could corrupt database and cause crashes during syncs

'news:' URIs without specific server had incorrect format displayed in status bar

'Mark' -> 'All Read' affected newsgroup messages that had not been fetched yet

Thunderbird could not reconnect to newsgroups after connection loss until restarted

Sending a newsgroup post appeared successful when it had actually failed

Saving a new draft retained superceded version

Thunderbird hung when auto-checking multiple accounts for new messages

Spam not checked with mail.server.default.check_all_folders_for_new on

Startup could be slow with large number of folders not using subscriptions

Saved search in unified folder resulted in server error

Thunderbird did not report refused POP3 connection

Remove message body retention policy was not functional

POP3 could stop downloading mail until restart

With auto-mark-read disabled, large mail still marked as read during load delay

IMAP "Show only subscribed folders" could not be changed without restart

POP3 deadlocked when server went silent without closing socket

Thunderbird could crash when mail folder was renamed or moved

NNTP server with invalid TLS certificate could not be added to certificate exceptions

Cancelled message send could not be retried and hung with SMTP timeout errors

Corrupted NNTP account data caused excessive memory use and startup crash

Multiple selected IMAP folders could not be moved or deleted together

Non-Latin IMAP keywords were lowercased and encoded incorrectly as MUTF-7

Message tags were lost when moving folder from local folder to IMAP folder

Removing a chat account threw an exception and failed to clear the UI

Enterprise policy use not indicated in about:preferences with link to about:policies

Language field in settings was empty after restart in Troubleshoot Mode

Primary Password policy was detected but not enforced for saved account passwords

Archived RSS feed messages were sent to the archive folder of default identity

Broken feed icon could prevent updating of feeds

Task reminders could fail for tasks without end dates or with shifted due dates

Calendar did not alert user for connection issues

Copying one recurring event occurrence failed to set the date when pasted

Could not copy an event in multiweek or month view by drag-and-drop

Duplicate attendees were added to invitations instead of being filtered out

Calendar discovery with certificate error displayed multiple exceptions

It was not possible to create date-only all-day tasks

Task percentage complete was not preserved separately from status in tooltips

Calendar invites were incorrectly marked processed after calendar sync completed

ICS event comments were not displayed in Thunderbird event details

Dismissed Gmail calendar reminder did nothing and item stayed visible

iCal imports misread unknown timezones as GMT, creating events at wrong times

Could not export local calendar as HTML

Cancelled filter edit dialog closed the message filter dialog

Visual and UX improvements

Security fixes

As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla

Original source