Zephyr is a fairly new Ajax-based MVC framework for PHP. It builds on the Smarty template engine, DAL data access layer, CPAINT remoting framework, and Prototype Javascript library.

The project has just entered beta 2.0, and maintainer Hasin Hayder sent us a summary of the improvements.

1. Prototype is now a part of Zephyr
2. SQLite support
3. Multilevel Filters
4. Multiple pre action processors
5. Supports Multiple database concurrently (From same/different providers)
6. Overall performance tuning
7. Embeded script execution
8. Multibyte strings are supported
9. Package Initializers

[Source:  ajaxian.com]