The Lightroom 2.1 release candidate is now available on Adobe Labs. The ‘release candidate’ label indicates that this update is well tested but would benefit from additional community testing before it is distributed automatically to all of our customers. The Lightroom team would like the community to help verify the quality of this update through normal usage as this will ensure that the application is tested on a diversity of hardware and software configurations not available internally at Adobe. The goal of this release is to address several bugs that were introduced with the release of Lightroom 2.0 and provide additional camera raw support. The Labs page linked above has detail on the changes. Tom Hogarty has also posted about it at Lightroom Journal.