> jsf-api-2.1.20
> jsf-impl-2.1.20
From the JSF 2.1 specification:
Other Java™ Platform Specifications
JSF is based on the following Java API specifications:
- JavaServer Pages™ Specification, version 2.1 (JSP™)
- Java™ Servlet Specification, version 2.5 (Servlet)
- Java™2 Platform, Standard Edition, version 5.0
- Java™2 Platform, Enterprise Edition, version 5.0
- JavaBeans™ Specification, version 1.0.1
- JavaServer Pages™ Standard Tag Library, version 1.2 (JSTL)
Therefore, a JSF container must support all of the above specifications.
WebSphere Application Server 6.1 is a J2EE 1.4 implementation and only supports Servlet 2.4.
You should ideally move to WAS 8 as Java EE 6 platforms support JSF 2 by specification.