Thunderbird 155.0 (64-bit)

What's new in this version:

New:
- S/MIME popup shows signature, digest, encryption algorithms and key sizes
- Default address book for manually added contacts configurable with mail.addr_book.add_item_default_uri
- Enterprise policy DisableQRExport can disable QR export
- OAuth add-ons can override built-in settings for selected domains and hostnames
- Manual account config streamlined with Exchange, Graph, and custom OAuth support
- Custom OAuth support for IMAP and SMTP servers
- PKCE and external browser fields added to custom OAuth settings
- Enterprise policy DisableExperimentalFeatures for disabling experimental features

Fixed:
- Unread count dock badge disappeared on macOS restart when no mail window opened
- IMAP tags did not sync automatically across clients
- Embedded SVG images appeared broken when Display Attachments Inline was disabled
- Holding arrow keys failed to smoothly navigate the folder pane
- Mark and Tag menu bar items were disabled in search results
- Quick Filter ignored address book display names shown in message lists and headers
- Attachment filters could disappear or return no results in global search
- Body search failed for quoted-printable messages ending on a soft line break
- Failed encrypted send did not preserve draft
- Failed account setup left an incoming server that blocked account recreation
- Removing an account did not remove its OAuth token from the password manager
- Account Hub prompted for calendar credentials immediately after successful login
- Filters could copy empty messages to Local Folders during startup mail download
- Closing message filters wrongly warned completed newsgroup filters were running
- Autoscroll icon was missing directional arrows in scrollable messages
- Apple Mail text attachments may not appear in MIME messages
- Forwarded messages could display incorrect encoding
- Thunderbird could crash due to improper database memory handling
- Thunderbird could crash on shutdown while waiting for OAuth2 password entry
- Thunderbird could crash while loading mail folders
- Custom OAuth could not be disabled
- Legacy IMAP tag changes were not sent to the server and reverted after refresh
- Deleting an Exchange account retained the outgoing server settings
- CalDAV calendars with offline support could stop fully synchronizing events
- Offline cached ICS calendar changes were silently lost after reconnecting
- Thunderbird upgrade disabled composition toolbar
- Thunderbird upgrade disabled Settings menu for versions before macOS 13
- Windows jump list menu no longer functioned correctly
- Visual and UX improvements
- Security fixes