MongoDB 3.3.8 has been released as a development release and is not intended for production use. This release includes several new features and bug fixes, including support for decimal numbers, improved builds on Ubuntu 16.04 LTS, enhanced explain output, additional tests for validation, and the implementation of $graphLookup functionality. The release also includes startup warnings if running without access control. The MongoDB team encourages users to report any issues they encounter with this release.