BEP 46 was published years ago. Since then, plenty of articles have talked about what a great thing mutable torrents would be; and people have indicated that libtorrent supports them. When I look around, though, I can't find any mention of them in the documentation for major Bittorrent clients; and the proofs of concept, at least five years old, will require a bit of detective work to satisfy `npm install`. So, is that where things stand? A BEP, some musing that it would be cool, and broken code? Are there tools that work? If so, where?