uTorrent 1.9 Alpha build 14589

Copied from the uTorrent forum:



New alpha!

The main change is that uTP (UDP torrenting) is added and enabled by default.

It also has real-time transfer rate control and latency minimization.

This build will probably download slower than 1.8.1, particularly if the entire swarm is 1.8.1.What is not in 1.9:

UDP tracker



What is in 1.9:

uTP, the micro transport protocol. This UDP-based reliable transport is designed to minimize latency, but still maximize bandwidth when the latency is not excessive. We use this for communication between peers instead of TCP, if both sides support it. In addition, we use information from this transport, if active, to control the transfer rate of TCP connections. This means uTorrent, when using uTP, should not kill your net connection - even if you do not set any rate limits. In addition we now implement NAT hole-punching for uTP connections, so connectivity should be improved for peers that do not have their ports mapped.



What was in 1.8.1:

uTP, but connection attempts were not initiated by default, and there was no control over TCP as described above. You can enable it, but likely you will see the uTP connections not transfering much data, because they are pushed out of the way by TCP.



What this means for rate control:

You are still free to set rate limits and use external limiters. The "Automatic upload rate" control is flawed enough for most people that it will likely be removed once uTP is well tested and deployed, since it entirely supercedes that feature.



How to enable and disable it:

Preferences > Advanced, set bt.transp_disposition to:

255 - both TCP and uTP (default)

10 - uTP only

5 - TCP onlyChangelog:2009-02-13: Version 1.9 (build 14589)



Change: optimize torrent generator to move the largest file to the front of the torrent



Change: support TB, PB, and EB sizes in UI



Change: show revision number in HTTP user agentFeature: language selector and downloader before installer