Thunderbird 152.0 Available With New Features, Fixes, and Thundermail Integration

Mozilla's popular free email client Thunderbird has been updated to version 152.0. This release brings a handful of new features, interface improvements, and a substantial list of bug fixes, particularly around IMAP, Exchange, and calendar reliability.

What's New in Thunderbird 152.0

One-Click Thundermail Account Setup

The most notable addition for new users is one-click account setup for Thundermail accounts, Mozilla's hosted email service. If you already have a Thundermail account, getting it into Thunderbird is now seamless.

Security Devices in Enterprise Policies

Enterprise deployments now gain support for SecurityDevices in enterprise policies, making it easier for organizations to enforce hardware security tokens and smart card configurations across managed installations.

What's Changed

• Button labels for creating accounts, calendars, and address books now consistently say "Add" instead of "New," making the interface clearer.
• Gmail OAuth has been updated to use PKCE (Proof Key for Code Exchange), improving authentication security.
• Mail server hostname is now also checked when detecting address books and calendars during account setup.
• The "Hide completed tasks" option in the calendar now also hides cancelled tasks.

Bug Fixes Highlights

This release is especially notable for its breadth of fixes:

• Wrong monitor alerts: New mail notifications no longer appear on the wrong screen in three-monitor setups.
• Spam notification timing: Spam messages no longer trigger new mail alerts before being filtered to the Spam folder.
• Exchange/EWS reliability: Forwarding or redirecting Exchange messages no longer fails with NS_ERROR_OUT_OF_MEMORY. EWS folders in Trash are now hard-deleted as expected.
• Thread view corruption: Several fixes address message ordering, collapsible thread display, and view corruption after delete/undo operations.
• IMAP improvements: "Show only subscribed folders" can now be toggled without restarting. Notifications for already-read emails after sleep/wake are suppressed. Up to 1,000+ messages can now be deleted at once on Microsoft 365.
• PGP fixes: "Edit as New Message" and inline Forward now work correctly with PGP-signed messages. BCC recipients are no longer incorrectly included in signed email headers.
• Calendar: Duplicate attendees are filtered from invitations. Calendar acceptance now correctly distinguishes between a single occurrence and a full series.
• Security fixes are included. See Mozilla's security advisory.

Download Thunderbird 152.0

Thunderbird 152.0 is a free download for Windows, macOS, and Linux.

• Official download: thunderbird.net
• Release notes: thunderbird.net/152.0/releasenotes
• UpdateStar page: Thunderbird on UpdateStar