On May 7, 2015, Suyog Rao announced the release of the fourth release candidate (RC4) for Logstash 1.5.0, addressing significant bugs found in RC3. The update rectifies a regression in filter chaining affecting periodic flush filters like multiline and metrics, and resolves an issue with the Lumberjack input plugin, which previously failed to properly timeout connections in back pressure scenarios, leading to increased memory usage and potential crashes. To mitigate this, an upper limit of 1000 Lumberjack connections has been implemented, although further improvements are planned. Users are encouraged to download RC4, test it, and provide feedback through GitHub issues, pull requests, or social media interactions.