We will provide help to migrate from EPP 4.3 to EPP 5.
About level of compatibility, obviously many things have changed, the portlet container is exactly the same though.
EPP 4.3 is still supported for the next 4 years
This posting is very old and I'm sure by now, we must have a nice documentation avialable for the community to migrate Jboss Portal 2.x.x applications which was deployed in JEAP 4.x.x to GateIn 3.1 deployed on JEAP 5.1.1(Red Hat certified). I kindly request to share this information to the community and thus helping the people in the forum in saving time on reinventing the solutions for already known problems as part of this migration.