MongoDB 3.0.5-rc2 has been released as a release candidate for testing purposes, addressing several performance and stability issues, including reduced throughput due to concurrent oplog tailing, server crashes during initial replication sync, and slow full text search functionality under WiredTiger storage engine. This release is intended to be a recommended upgrade for 3.0 users, with the next stable release of 3.0.5 planned in the future. The MongoDB team encourages users to report any issues found during testing.