Neo4j has released a milestone version, "Kiruna Stol", with significant performance improvements and additions to the REST API, including support for arbitrary Lucene queries through both Java APIs and the REST interface. The new index component based on Lucene 3.1 brings impressive improvements in index lookup speed, making operations twice as fast depending on use cases. To take advantage of these changes, users must upgrade their index store due to compatibility issues with previous Neo4j versions. The release also introduces a significant technical change by reverting the default implementation of Write Ahead Logs from memory mapped files to a buffer backed equivalent, providing speedups, especially for small transactions. Users are encouraged to download the latest milestone and share their feedback.