In terms of the MongoDB 2.6 changes, "You’ll see the benefits in better performance and new innovations. We re-wrote the entire query execution engine to improve scalability, and took our first step in building a sophisticated query planner by introducing index intersection. We’ve made the codebase easier to maintain, and made it easier to implement new features. Finally, MongoDB 2.6 lays the foundation for massive improvements to concurrency in MongoDB 2.8, including document-level locking."
Additionally, "MongoDB 2.6 brings security, integration and analytics enhancements to ease deployment in enterprise environments. LDAP, x.509 and Kerberos authentication are critical enhancements for organizations that require a single authentication mechanism across their entire infrastructure. To enhance security, MongoDB 2.6 implements TLS encryption, user-defined roles, auditing and field-level redaction, a critical building block for trusted systems. IBM Guardium also now offers integration with MongoDB, providing more extensive auditing abilities."
MongoDB developers are working on new automation and hosted/on-premises options.
More details on today's MongoDB 2.6 release can be found via the MongoDB blog.