Portlet applications don't need to change, including JSF portlets that can now benefit from the first JSF PortletBridge to be JSR-329 compliant.

The only potential change deal with the portlet descriptor (portlet.xml), its parsing has been made more strict and will need to strictly follow the portlet schema. Previous versions of JBoss Enterprise Portal Platform were tolerant to ordering mistakes. Tools like JBoss Tools can help you making sure that your descriptors are correct.

The official Portlet 2.0 schema can be found here: http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd