We've shipped Betterbird 140.12.0esr-bb24 today. Please refer to the Release Notes for full details.
This release contains fixes some important bugs:
Cancel sending had broken in Thunderbird 135, and no one noticed. We've already written about it. This is fixed in Betterbird 140 now, the Thunderbird folks fixed it for release 153.
Secondary sort is not a well-known feature. To make it a bit more obvious, Betterbird shows secondary sort indicators on column headings in table view where appropriate. Those weren't aligned correctly in default and relaxed densities.
Betterbird had a widely misunderstood feature where the user could zoom images in links if they were oversized. We had a few complaints since people didn't recognise the link, and if they did, had to used the context menu to open it. Finally a user sent us a sample e-mail which was rendered quite incorrectly due to the feature. That was the last nail in the coffin and the feature was dropped.
Lastly this release fixes a few issues with reversed sorting and collapsing a thread to the most recent message. This is driven be preferences mailnews.reversed_threading and mailnews.collapse_thread_to_most_recent. Check this article for details about those function.