I'm currently try using batmand-experimental Rev.972.
First the visualisation server does not show any connections. Have two routers with batmand-exp rev 972 running. It seems that this batman version is not compatible with the vis-server.
When I use the old version of vis, I get the dot information when I call "telnet localhost 2004". I assume that the batman-exp implementation still uses the old compatibility version for vis.