The Py2neo v4 release introduces significant improvements, including a revamped Graph constructor with enhanced settings and authentication options. The API has been expanded to include several logical layers of abstraction, such as the Entity API, which provides CRUD operations on Node and Relationship objects, and the OGM API, which enables creation of GraphObjects that model relationships and properties. Additionally, new features like reporting, analytics, and data science integrations have been added, including support for multiple output formats and integration with popular libraries like numpy, pandas, and sympy. The Cypher lexer has also been implemented for tokenization and syntax highlighting in the interactive console. Furthermore, the `py2neo` command-line tool has been introduced, providing a simple way to manage Neo4j instances, download distributions, and run Cypher queries.