Feature

Performance and Scalability Enhancements
The use of TarPM -- Tar Persistence Manager -- for performance and scalability improvements. TarPM is a disk-based persistence technology that uses the standard Tar file format and is suitable for high data creation and modification. It has been optimized for use for JCR-based repositories -- in particular it takes advantage of the key-value pair data structure of the CRX and maintains index files for fast access to content.
TarPM provides both vertical and horizontal scalability: * Vertical - supports Data Store technology * Horizontal - supports clustered environments
Availability and Backup/Recovery
Administrators now have the ability to add or restore cluster nodes at run-time and they can perform hot backups at any time thanks to TarPM.
Developer Enhancements
A few improvements on the developer front should help developers build faster, Web 2.0-based applications.
REST
CRX 1.4 comes with a new web development framework based on REST and Apache Sling called the CRX Launchpad. This new framework is supposed to allow developers to use their preferred programming language -- meaning it's not bound to Java.
Apache Jackrabbit
This release of the CRX is based on the latest unmodified official Jackrabbit release and is "code drop-in" compatible. What does this mean? * Easily upgrade to the Day CRX from an Apache Jackrabbit Repository without configuration changes or a content migration * Apply bug fixes to the CRX that were implemented in Apache Jackrabbit and vice versa * Easily migrate to the CRX from Jackrabbit * Support for Source Code Debugging of Apache Jackrabbit components is now included
Don't forget about Day's JCR Cup competition. They extended the entry deadline to September 30th to allow more time for entrants to develop their creations. Whether you are an administrator, developer or manager, you can learn more about Day and their solutions from a set of presentations on their website. These presentations were given at their Business and Technology Summit in May of this year. There's a detailed technical presentation on TarPM.