What's new in 2.4.0.0
1. What's new in Azureus 2.4.0.0

1.1 Encrypted/Obfuscated Data Transfer
Support for encrypting the data between Azureus and other compatible clients is included. This both provides a level of protection of data and can help with ISPs that block or restrict peer-to-peer traffic.

1.2 High Speed LAN Transfers
Multiple copies of Azureus running on the same local network support high speed direct connections.

1.3 Improved Download Algorithm
The algorithm used to determine which pieces of a download to request from which peers has been rewritten to improve its behaviour and performance.

1.4 Webseed Support
Basic webseed support is included. Webseeds will only be used when a download's availability is less than 1.0.

1.5 Other
Various user interface improvements.
Performance improvements.
Bug fixes.

2. Full ChangeLog
http://azureus.sourceforge.net/changelog.php?version=2.4.0.0