Neo4j 2.3 is a significant release that focuses on building bigger and better applications, with new features such as a fully off-heap cache, faster query optimizer, schema improvements, and official support for Docker. The release introduces several key enhancements including intelligent applications at scale, eliminating the JVM-based object cache, smarter Cypher query planner, and improved performance in concurrent read scaling. Additionally, Neo4j 2.3 includes features such as property existence constraints, Spring Data Neo4j 4.0, Windows PowerShell support, faster backups, upgrades, and bulk loading of data, making it an exciting release for developers and users alike.