The troubled history of Mozilla’s Thunderbird could fill a book, from an extensive period on life support to its shift away from non-profit ownership. Even as development has resumed on the once moribund email client, criticisms remain over its stability and features.

For those frustrated by Thunderbird’s continuing issues, there may be a solution: Betterbird, which as its name implies, is a fork of the main Thunderbird client.

Described as a 'soft fork' of Thunderbird, Betterbird chooses to follow the ESR releases for security reasons. This means Betterbird is built from the latest stable release of Thunderbird and won’t diverge from it over time.

Despite tracking closely to its parent, Betterbird claims to be 'Thunderbird on steroids', promising exclusive new features and bug fixes alongside those bug fixes submitted upstream to benefit Thunderbird at a future date.

What makes Betterbird stand out is the fact its lead developer is none other than Jörg Knobloch, the man who almost single-handedly kept Thunderbird going during its darkest hours. After becoming its first employee, he found himself cast out for raising concerns over a "lack of commitment to quality, a completely missing QA team and defective bug triage" shortly before the project switched to a for-profit corporation ownership model.

What might have been a major loss to Thunderbird users has turned out to be a blessing in disguise. Betterbird is so closely related to Thunderbird it’s possible to run both side-by-side using the same profile. This allows users to easily compare the two and decide which one is best for their needs.

Betterbird’s highlights reel demonstrates how the app attempts to address long-standing issues – one major feature (a multi-line inbox view like that used by Outlook) has been a feature request in Thunderbird since 2003, for instance.

Elsewhere, other tweaks include customisable options like vertical tabs, account colours and the ability to view attachments above emails, as well as more practical benefits like support for complex search terms (including regular expressions). Linux users gain a system tray icon displaying the number of new messages for the first time, and you can choose a different startup folder too. Crucially, it’s all rounded off by fixes for bugs left untouched by Thunderbird’s development team.

In practice, many of these tweaks are disabled by default, so out of the box it’s hard to tell the difference between Betterbird and Thunderbird. But while it may take a little time configuring the look and feel to get a proper appreciation of how Betterbird compares for those looking for UI improvements, anyone whose prime concern is stability can give it a road-test without having to make any adjustments to a new application. It’s a win-win for the community.

Betterbird 115.6.1 is available now as a free, open-source download for Windows 7 64-bit or later, macOS 10.0 or later, and major Linux distros, including Debian, Ubuntu and Linux Mint. A portable build is also available for Windows users.