Neo4j has released its 2.0 Milestone 4, which introduces several key changes to improve the database's performance and usability. Starting with this release, Neo4j requires Java 7 to run, as Java 6 is no longer supported by Oracle due to reaching public end of life in February 2013. The new version also enforces mandatory transactions for read operations, making it more efficient for handling load. Additionally, Cypher's query language has undergone changes, including the removal of syntactic sugar property handling and a change in the separator for collection functions from a colon to a pipe symbol. The database also introduces an expanded set of math functions and a new Cypher parser with improved efficiency, correctness, and usability.