BitTorrent Protocol and Client Gone Closed
Latest version of BitTorrent client (v 6.0), which is based on closed-source uTorrent (acquired a while back), has not been released, neither has been the protocol specs. The “official” BitTorrent client has never been very popular compared to other protocol implementations like Azureus and uTorrent.
Protocol specs, although technically closed, are available with very tightly maintained SDK license. And, all previous version of protocol as well as the client are available openly.
In lifecycle of any technology “The step after ubiquity is invisibility“. I always hoped BitTorrent to follow that curve. Not anymore probably.