MongoDB 2.8.0-rc0 Release Candidate has been announced, featuring improved concurrency, compression, and pluggable storage engines, including WiredTiger, which provides on-disk compression reducing disk I/O and storage footprint by 30-80%. The release is now available for testing and bug hunting, with a chance to win prizes for contributing to the quality of the release. The Bug Hunt rewards community members who contribute to improving MongoDB releases through testing, with winners announced on December 9.