Cydia was recently updated to support Apple's updated API's in iOS 4.2. This particular Cydia update was quite the major overhaul, and there is no option available (yet) within Cydia to update to the newest version automatically.
Besides iOS 4.2 support, there are several long-awaited improvements in this version of Cydia.
The most noticeable improvement in this update is a huge performance boost throughout the whole application. Everything is faster. Once Cydia does the initial restructuring and downloading after you first install the update, you should notice an immediate boost in speed as you navigate the app. That means less of the dreaded loading wheel and more of actually accomplishing what you want to do...
