A better Mozilla Thunderbird.
Betterbird is a fine-tuned version of Mozilla Thunderbird, Thunderbird on steroids, if you will.
Betterbird is a soft fork of Mozilla Thunderbird. Soft fork means that it is closely following the Thunderbird Extended Support Releases (ESR) therefore avoiding the mistakes of other forks which quickly lost track of upstream Thunderbird, thus opening users up to security vulnerabilities.
If you like Thunderbird but are discouraged by too many bugs, then give Betterbird a try. It is 100% compatible with Thunderbird's ESR version. You can install the same dot release of Thunderbird in parallel and switch between Betterbird and Thunderbird on the same profile without problems and without needing the -allow-downgrade command line switch.
Betterbird is better than Thunderbird in three ways:
Please refer to the feature table on the website for specific examples about the Betterbird being simply better.
Updated on May 10 2023
Full changelog available here.