Have you ever wondered why Betterbird follows the Thunderbird ESR (Extended Support Release) channel and not the Thunderbird Release channel? The answer is easy: The Release version is riddled with regressions that slipped through the beta phase. Even Thunderbird users seem to be aware of that, as according to the latest published statistics, and despite the best effort of the Thunderbird folks to push their Release channel to users, 73% are still on ESR. They prefer stability to fresh regressions and partly implemented and non-functional new features.
Three examples from the current version 144. This is shipping with the new reworked so-called Account Hub, which is very buggy, this bug only has 22 duplicates. Next, 144.0 shipped on 14th October 2025 with a bug, causing the taskbar button of the compose window to disappear from the taskbar. This was quickly fixed with a new release 144.0.1 two days later. Last not least localisation of IMAP folders for drafts, templates, sent messages, etc. is broken. Users of localised versions see the English names.
One argument for the Release channel has been, that new features would reach users faster. While this is true in theory, the practice is different. For example, the much-touted Microsoft Exchange integration via EWS is still not feature-complete in the current release. Users are left to find out in which way their the Exchange account behaves like normal local or IMAP accounts, and which features still need to be implemented.
In Germany there is a term for this: "Bananaware", the product ripens on customers' systems.