Thunderbird 137 Released – Fixes, Improvements, and What’s New

Thunderbird is a free, open-source email client developed by the Mozilla Foundation, best known for its powerful customization options, support for multiple email accounts, and strong security features. Available for Windows, macOS, and Linux, Thunderbird is a popular choice among users who prefer a desktop-based email solution over webmail. With features like tabbed email, a built-in calendar, and robust junk mail filters, it’s designed for both casual users and professionals alike.

Over the years, Thunderbird has evolved into more than just an email client. It now supports chat, RSS feeds, and advanced encryption through OpenPGP, making it a complete communication suite. Frequent updates ensure compatibility, improved performance, and enhanced user experience across platforms.

What’s New in Thunderbird 137?

The latest release, Thunderbird 137, focuses primarily on bug fixes and usability improvements, with a few notable changes. On Windows, file names are now used when storing mail folders, which should help with file organization and compatibility. Meanwhile, on Linux, the system tray icon has been temporarily disabled until it gains proper functionality—avoiding confusion or false expectations.

A long list of bugs has been addressed, improving accessibility, performance, and reliability. Notably, in-app notifications now display correctly in high contrast mode, and long-standing issues with mbox repair on macOS have been fixed. Users will also notice smoother performance when opening .eml files, scrolling through RSS messages, or handling large folders. Problems with replying to messages, OpenPGP attachments, and visual inconsistencies in the UI have all been resolved.

IMAP users benefit from fixes to the “Undelete” function, which previously misbehaved when multiple messages were selected. Improvements to search functionality, message threading, and moving messages across folders further enhance productivity. Several crash scenarios—such as searching during shutdown or sending failed news messages—have been eliminated, leading to a more stable experience.

Final Thoughts

Thunderbird 137 is a maintenance-heavy release, focusing on quality-of-life improvements rather than new features. This kind of update may not make headlines, but it’s crucial for maintaining a dependable email experience—especially for power users with complex configurations and high-volume email traffic.

The Thunderbird team continues to demonstrate a strong commitment to user feedback and platform stability. From fixing minor UI inconsistencies to addressing critical issues with encryption and server compatibility, every improvement reflects attention to detail. These changes make Thunderbird not just usable, but enjoyable for both casual and advanced users.

With more fixes under the hood and ongoing enhancements, Thunderbird remains a solid choice for anyone who values privacy, flexibility, and control over their email workflow. Version 137 might not bring flashy upgrades, but it lays down important groundwork for future innovations—while ensuring that today’s users have a smooth and secure experience.