Thunderbird 150.0 It is now available as a new stable version of Mozilla's popular email and calendar client for Windows, macOS, and Linux. Following the release of Thunderbird 149This is a major update that combines practical day-to-day improvements with a number of bug fixes and security patches for the web engine that powers the application.
In addition to strengthening security, this delivery focuses on Improve working with encrypted messages and PDF attachmentsThe update refines the initial setup experience and improves various aspects of the interface. For individual users and organizations that rely on Thunderbird daily, this update represents a significant step forward in stability, privacy, and ease of use.
Key updates in encrypted email handling
One of the most relevant changes in the Thunderbird 150 is the ability to search within the body of encrypted messages Both with OpenPGP and S/MIME. Until now, locating information in protected emails could be tedious; with this version, the client allows you to directly search the content of those messages from the integrated search engine, without any additional steps for the user.
The update also includes support for generating Unobtrusive Signatures in OpenPGPThis digital signature format is designed to make signed messages less visually intrusive, especially for those who don't use OpenPGP. In this way, signatures still provide guarantees of authenticity without unnecessarily cluttering the email's appearance in the recipient's inbox.
A more versatile PDF viewer with bugs fixed
The built-in document viewer gains prominence with the option to Reorder the pages of a PDF directly from ThunderbirdFor users who receive contracts, reports, or lengthy documents, being able to rearrange pages without leaving the email client greatly streamlines the workflow with attachments.
Along with this functional improvement, the following have been applied Solutions to vulnerabilities detected in the PDF viewerThese improvements address clickjacking risks and potential data leaks, aligning with the security warnings also published for Firefox. Thus, the component is not only more useful but also more robust against remote attacks that attempt to exploit vulnerabilities when opening attachments.
Interface improvements, customization, and contacts
In the general settings section, Thunderbird 150 introduces adjustments that, while not spectacular, refine everyday use. The list of “Recent Destinations” now supports alphabetical orderThis makes it easier to find frequently used folders or locations when archiving messages.
The address book becomes more practical thanks to the option of Copy contacts to the clipboard in vCard formatThis standard is common in many email and contact management applications, making it easier to exchange contact records between different programs and services without having to manually export and import.
In terms of visual aspect, the new version allows you to choose a custom accent color in the appearance sectionThis feature provides an extra margin of customization that can be useful both for adapting the interface to the aesthetics of the operating system and for better distinguishing usage profiles, without changing the overall design of the program.
A more user-friendly calendar, especially on touchscreens
The calendar module, which comes standard with Thunderbird, also receives attention. Specifically, the views of Monthly and multi-weekly displays can now be scrolled using touchscreensThis improvement is especially relevant in convertible laptops, tablets with keyboards, or touchscreen devices, which are becoming increasingly common in work and educational environments.
In addition, the option to “Move to new window” for the calendarThis allows you to separate the agenda from the rest of the client's panels and work with it independently, for example, on a second monitor.
New account, more guided start
For those installing Thunderbird for the first time, version 150 opens a startup program. Account HubThis section guides the user through the setup of mailboxes, calendars, and other compatible services. The goal is to make the initial setup less confusing and to allow for the creation of IMAP, POP3, or Exchange accounts with fewer steps and less room for error.
Extensive round of bug fixes
Beyond the visible features, the development team has fixed about a dozen problems reported in previous versionsThis impacted stability and overall performance. Among the bugs fixed was one that could cause the program to close unexpectedly when creating new folders under certain conditions.
Incidents have also been addressed with POP3 email downloads that could get blocked including restarting the application, as well as memory leaks related to Exchange servers that maintained mutual object references.
Some have also been resolved Authentication problems in Exchange accountsThese issues, which in some cases prevented proper connection, have been resolved, and inconsistencies in the calendar where the date and time axes appeared swapped have been corrected. Additionally, the option to open the calendar in a new window is once again available after having been removed in a previous version.
Accessibility and behavior in the Microsoft Store version
In terms of accessibility, Thunderbird 150 corrects several incidents affecting screen reader usersThese included the names of certain mailboxes that were not advertised correctly and an incorrect message count in the folder panel, which made it difficult to track the inbox and other locations using assistive technologies.
On the other hand, the edition distributed through the Microsoft Store fixes a bug This caused the application to fail to open when clicking on news:// links or when attempting to open .eml files from the system. With the new version, these elements now launch with Thunderbird as expected, eliminating the need for manual shortcuts.
Enhanced security on the desktop client
Along with the functional improvements, the update comes with multiple security patches that affect both Thunderbird itself and the underlying web engineDozens of vulnerabilities have been closed, including some classified as high severity, related to code execution, bypassing security restrictions, information leakage, and other common vectors in remote attacks.
In practice, these corrections reduce the attack surface when they are opened messages in HTML, remote content, or potentially malicious attachmentsSince the client relies on the same rendering technology as the Firefox browser, patches applied in this area directly benefit email users, which is especially relevant in corporate environments where email remains a frequent avenue for attack.
Compatibility and availability
Thunderbird 150.0 is available for Windows 10 or later, macOS from 10.15 (Catalina) and GNU/Linux distributions that have GTK+ 3.14 or higher. In the Linux ecosystem, the package is also offered in Flatpak format, where the beta identifier has been updated to org.mozilla.thunderbird to standardize it with the name used officially.
Existing users can get the new version through the Thunderbird's integrated update system or by downloading the installer from the project's official website. In most cases, the update is distributed automatically, so simply restarting the application when prompted will complete the process.
For those who need extended support cycles, Mozilla maintains in parallel a ESR (Extended Support Release) branch with more conservative update cadences. However, Thunderbird 150 does not belong to that extended support line, so it is intended primarily for users who want to incorporate the latest features and fixes as soon as they are released.
With all these changes, Thunderbird 150 establishes itself as a version that prioritizes security and strengthens the management of encrypted email, while introducing practical improvements in the PDF viewer, calendar, contacts, and interface customization—a balance that may be especially interesting for those who use the Mozilla client daily in personal and professional environments.
