According to The How-To Geek, Mozilla has released Thunderbird 146 to the stable channel as of today, alongside an update for the Extended Support Release version to 140.6. The feature list for version 146 is notably slim, highlighting only two user-facing changes: the ability to set a preferred OpenPGP keyserver directly in the interface and the migration of existing account logins to modern AES cryptography. This follows the more significant native Microsoft Exchange support that landed in November’s version 145. The Thunderbird 146 update is packed with over two dozen bug fixes addressing crashes, UI glitches, and account management issues. Meanwhile, the Thunderbird ESR 140.6 update focuses primarily on delivering the same security patches for environments that prioritize stability over new features.
A Maintenance Release
So, this is basically a “fix-it” release. And that’s fine, honestly. After the pretty big deal of finally adding native Exchange support last month, the team is clearly in cleanup mode. The two noted features are for fairly niche audiences—OpenPGP power users and sysadmins ensuring crypto standards are up to date. The real meat is in that long list of bug fixes. We’re talking about crashes when moving folders, attachment deletion mix-ups, and a bunch of quirks in the relatively new Account Hub. It’s the unglamorous work that makes software feel solid and reliable. Here’s the thing: for a project like Thunderbird, which positions itself as a robust, professional desktop client, these stability updates are arguably more important than flashy new features for most of its core users.
The ESR Path and User Choice
This dual-release strategy with the ESR channel is smart. It mirrors what Mozilla does with Firefox and gives organizations, or even just cautious individuals, a clear choice. You can ride the regular release train for the latest tweaks and fixes, like the ones in version 146. Or, you can stick with the ESR version and only get major updates every year or so, with only critical security patches in between. The announcement makes it clear: if you’re on ESR 140.6 and want any features from versions 141 through 146, you need to switch channels. It’s a good reminder that you have to actively manage which version you’re on, especially in a business setting.
The Bigger Picture for Thunderbird
Look, a release like this is quiet, but it doesn’t mean the project is stagnant. The article hints at the ongoing work on mobile apps and the Thunderbird Pro services. There’s also that 2026 mobile roadmap to consider. I think what we’re seeing is a mature desktop client being steadily maintained while the team’s ambition expands into new areas. For day-to-day users, that’s probably ideal. You get a reliable workhorse that gets periodic tune-ups (and all the security fixes), while the future of the platform is being built elsewhere. It’s a pragmatic approach for an open-source project with limited resources.
Should You Update?
Absolutely, yes. If you’re on the regular release channel, grab Thunderbird 146. The bug fixes alone are worth it, especially if you’ve encountered any of those folder or attachment issues. The security updates are the most critical part, as always. For ESR users, moving to 140.6 is a no-brainer for the same reason—it’s all about patching vulnerabilities. Just don’t expect a dramatically new experience. This is the plumbing and wiring of the app getting an inspection, not a new coat of paint. And sometimes, that’s exactly what you need.
