MyFaces is known to work with and was tested with the following environment:

Java
- JDK 1.4.0_01

Servlet Container
- Tomcat 4.0.4 (4.1.x is known NOT to work by now!)
- JRun 4 SP1a

JSF API
- JSF-API from the JavaServerTM Faces v1.0 Reference Implementation Early Access 3