ClassCastException upon trying to invoke asynchronous method in bean running in EAP7.1 from 7.0 legacy EJB client

Mar 17, 2017 7:25:36 AM org.jboss.as.quickstarts.ejb.asynchronous.client.AsynchronousClient fireAndForget
INFO: The server log should contain a message at (about) Fri Mar 17 07:25:51 UTC 2017, indicating that the call to the asynchronous bean completed.
Exception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to java.util.concurrent.Future
	at com.sun.proxy.$Proxy0.longerRunning(Unknown Source)
	at org.jboss.as.quickstarts.ejb.asynchronous.client.AsynchronousClient.getResultAsync(AsynchronousClient.java:88)
	at org.jboss.as.quickstarts.ejb.asynchronous.client.AsynchronousClient.main(AsynchronousClient.java:159)