Mongoose 3.7.0 is an unstable release, meaning it contains potentially breaking changes and should not be used in production. The largest change is the use of Mquery to power querying, which allows for custom query functionality and reusability. Benchmarks have been added to measure performance, with plans to expand them further. Geospatial support has been improved, including $geoWithin, Haystack indices, and $geoNear command. An Aggregation Builder has also been added, allowing users to build aggregation queries in the same way as normal queries.