Thunderbird 157 is now available, bringing a long list of fixes across mail handling, authentication, encryption, calendars, and account setup, along with a couple of new controls aimed at enterprise deployments.

One notable fix addresses an issue where Thunderbird’s status bar could remain active after an operation finished, potentially pushing CPU usage to 100%. The release also fixes cases where the message list displayed the wrong sender and where sent messages silently failed to save to the IMAP Sent folder.

OpenPGP users get several improvements. Thunderbird 157 fixes an issue that could cause valid RSA OpenPGP keys to be rejected and prevent encryption. Key discovery can now correctly locate replacement keys after an existing key is revoked. The client can also display remote content in OpenPGP messages encrypted with integrity protection.

On the authentication side, intermittent Gmail OAuth2 failures on Windows have been addressed, along with SMTP OAuth2 problems caused by large access tokens. Exchange users should see more reliable NTLM authentication after password changes. Another fix targets SMTP AUTH LOGIN failures following username challenges.

Moreover, Thunderbird could hang while waiting for an IMAP server greeting during account setup. Pending message moves inside the same IMAP account could sometimes make messages disappear. Both issues are fixed in version 157. Plus, manual IMAP and POP configuration is also simplified, as specifying a port is now optional.

Calendar and contacts users are covered too. The update fixes recurring events appearing beyond their configured end date, outdated CalDAV task content after synchronization, CalDAV invitations failing when accepted before a calendar synced, and some CardDAV address books failing to synchronize.

On the enterprise side, administrators now have two additional policies: DisableChat, which disables Thunderbird’s Chat functionality, and DisableFileLink, which disables FileLink. Plus, the built-in Thundermail add-on has been updated to version 2.0.16.

Rounding things out are fixes for disappearing inline images in edited drafts, incorrectly triggered message filters, blank Yahoo messages under certain MIME handler configurations, the Quick Filter keyboard shortcut, and various visual and UX issues.

For additional details, see the announcement.