http://www.utorrent.com/downloads

First STABLE release, anyways. This new version uses the µTP protocol.

The effect of this should be very positive for end users:

(1)    A µTorrent client no longer needs to be limited to some arbitrary rate limit for fear that it will saturate the connection and crowd out all other applications – µTP  will take care of this automatically at the level of each packet transferred. On average this will likely result in actual average download speeds increasing across the board.

(2)    Because the µTP protocol is designed to mitigate congestion on networks caused by poorly configured BT clients, it is possible that ISPs will take a friendlier view towards the protocol than they often take towards the older type of BT protocol. This *may* mean less BT throttling and faster download speeds for end users. There’s some early anecdotal evidence that this is indeed the case, and certainly ISPs to whom we have presented the technology have so far reacted quite warmly.

(3)    Although there have been some concerns voiced that users “don’t want their clients to throttle themselves”, of course the reality is that if the line is congested then nothing can be transferred. You may want to drive at 80mph, but if there’s a traffic jam you’re out of luck. µTP will mean that BitTorrent transfers are no longer the cause of congestion, and will enable the connections to automatically recover from a congested state much faster.

The effect on network operators will be also hopefully quite noticeable: We anticipate that a large proportion of BitTorrent traffic will start to actively monitor packet transfer speeds for any indication that there is congestion on the line. If there is even a tiny amount of congestion, no matter what caused that congestion, µTP will immediately slow itself down and allow the congestion to clear.

Of course network congestion is not the only concern of network operators, and we will continue to support efforts to enable ISPs to communicate preferred routing policies to clients (for example through the IETF’s ALTO working group). But we hope that to the extent that µTP is successful at mitigating internet congestion, it is interpreted as an exciting win for everyone involved.

I shall be checking this out...