ROS 0.6.0 has been released! Our big goals for this release were to make bag files more robust, add in UDP transport for C++ users and prepare for our upcoming releases of stacks (e.g. navigation). With previous releases, bag files would become unreadable if the messages they were recorded from were changed. The new bag file format enables bag files to always be read and comes with tools for migrating them in the event of changes. As a result of these updates, all of your existing bag files will need to be updated. There are more instructions on our more detailed change list.
Related to our bag file changes, we've also changed our md5sum calculation for message versions to make it easier to move, rename, and add comments to messages. You can now perform these changes without altering the md5sum.
We've added in UDP as an experimental transport to our C++ library. This UDP transport is currently point-to-point and targeted at low-latency applications for ROS, such as teleoperation.
Another major update is the introduction of the searchParam API to the Parameter Server. In the past, it was difficult to push node down into child namespaces and still have them share common parameters. For example, you may wish to set a parameter like the robot description in a parent namespace and have all children easily read from it. The searchParam API solves this problem by allowing you to search for a parameter in parent namespaces, returning the parameter key that is closest to your node's namespace.
There are many other updates in this release, so please consult the detailed list of changes. You can also consult our roadmap to get a preview of the remaining features we are planning for ROS as we move towards a 1.0 release.