290 Reasons to Upgrade to Apache Kafka 0.9.0.0 | Confluent

This post details numerous bug fixes and improvements in Apache Kafka 0.9.0.0, with a strong emphasis on correctness, reliability, and operability over new features. Specific technical details are provided for fixes related to replication (race conditions, min.insync.replica, replication lag), MirrorMaker message loss prevention, log cleanup, log compaction (especially for compressed messages), connection leak detection, broker metadata cache synchronization, request purgatory rewrite, and producer timeout enforcement. It also highlights the addition of a new distributed testing framework with over 100 new test scenarios.