In the past few months or so, it seems that Thunderbird has undergone changes. There is at least one very useful addon the development for which is not being continued because making it work under Thunderbird's current form would take to much resources. For example, [https://addons.thunderbird.net/en-us/thunderbird/addon/attachmentextractor-continued/ Attachment Extractor Continued] The development of this addon was "Continued" when there was such a change. With more recent changes, the current developer is not continuing the development. It seems that another addon developer has started to write this addon from scratch but it has a long way to go before it works. There does not seem to be a way to communicate directly with that developer. I've been satisfactorily using Thunderbird for many years now but I'm starting to wonder about the business model for feature and addon development.