these were changes between 4.2 and 5.x. The schema for 5.x unfortunately still contains these and does not mark them as deprecated (XSD does not provide a way to do so, we should probably remove them altogether in the 5.2 schema).
Just replace your <stateRetrieval/> element with a <stateTransfer/> element.
I have opened an issue to deal with this: https://issues.jboss.org/browse/ISPN-1970
thanks for the response. I think the first step is to remove all deprecated configurations from the configuration files shipped with the downloads and in GitHub. For users like me, I tend to look at the sample configuations in the code as reference.