From Mitchell Baker's blog post, it appears that it is Firefox that has diverging needs from Thunderbird. "Thunderbird and Firefox are interconnected in a few

From Mitchell Baker's blog post, it appears that it is Firefox that has diverging needs from Thunderbird. "Thunderbird and Firefox are interconnected in a few different ways. They are connected through our technical infrastructure. Both use Mozilla build and release systems. They’re connected through the sharing of some pieces of technology. The time has come when it is no longer effective for Thunderbird and Firefox to keep sharing the same technical infrastructure. Firefox and Thunderbird have diverging needs." https://blog.lizardwrangler.com/2015/12/03/thunderbird-update/ https://blog.lizardwrangler.com/2015/12/03/thunderbird-updat...