After update to vaadin 7.4.1: IllegalStateException Session has already bee

Hi,

after updating from vaadin 7.1.15 to 7.4.1 we get the following error when restarting the application via the

?restartApplication
parameter:

java.lang.IllegalStateException: Session has already been set. Old session: com.vaadin.server.VaadinSession@13cdda2d for vaadinServlet. New session: com.vaadin.server.VaadinSession@79dc5517 for vaadinServlet. com.vaadin.ui.UI.setSession(UI.java:421) com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:196) com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74) com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41) com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1408) com.vaadin.server.VaadinServlet.service(VaadinServlet.java:350) com.werum.pasx.base.ui.di.context.support.PasxServlet.service(PasxServlet.java:165) javax.servlet.http.HttpServlet.service(HttpServlet.java:803) We are using a ui scope (spring) and it seems that after the update the ui is not selected correctly from the ui scope.
Does anyone know what changes may cause the failure?

The parameter
URL_PARAMETER_RESTART_APPLICATION = “restartApplication”
in VaadinServer is deprecated.
What is currently the correct way to restart an application?