Mozilla Thunderbird 153 is now available as the latest stable release of the open-source email, calendar, contacts, and chat client. The most visible change is that OAuth authentication for mail accounts now opens in the system’s default web browser instead of inside Thunderbird.
This release also integrates Thundermail, Thunderbird’s own subscription email service, directly into the application, removing the need to install a separate add-on. Plus, unified folders now display an account color indicator with a tooltip showing the corresponding account name.
Moreover, Thunderbird can now decrypt certain Apple Mail messages that hide the recipient key ID. Additionally, performance has improved when decrypting messages and opening emails with OpenPGP keys. The update also fixes key-refresh failures and improves error reporting when importing public keys with experimental packets.
Exchange Web Services support received several corrections as well. These include an OAuth option for manually configured EWS accounts, working new-mail notifications without opening the folder first, proper unread status for sent messages, improved NTLM authentication behavior, and the return of the Reply All button for messages with multiple recipients.
Thunderbird 153 also addresses multiple IMAP problems. An issue that could delete INBOX and other mailbox files during migration of old IMAP profiles has been resolved. Tags no longer reappear after removal, several selected folders can be moved or deleted together again, and tags are preserved when folders transfer from local storage to an IMAP account.
Several message-composition and attachment bugs have also been fixed:
Ctrl+Enterno longer opens an attachment instead of sending the message.- Dragging email addresses between compose windows now correctly adds recipients.
- Composing with PDF attachments no longer opens the PDF instead of creating a new email.
- PDFs opened in Thunderbird tabs can now be saved with Ctrl+S.
- PDFs can also be scrolled using the space bar.
On the stability side, developers fixed crashes during shutdown, folder copy or move operations, Find and Replace All, and attempts to copy an empty message list. Auto-compaction could corrupt the message database and cause crashes during synchronization. This issue has now been corrected.
Additional fixes cover CardDAV redirects, NNTP accounts, multi-monitor notification positioning, SMTP timeouts, message filters, Primary Password policy enforcement, recurring calendar events, invitation processing, and the display of comments imported from ICS files.
For more details, see the release notes.
