code: private boolean checkVersion(final KNXnetIPHeader h)
  	{
  		if (h.getVersion() != KNXNETIP_VERSION_10) {
  			status = "protocol version changed";
  			close(CloseEvent.INTERNAL, "protocol version changed", LogLevel.ERROR, null);
  			return false;
  		}
  		return true;
  	}
docs: Checks for supported protocol version in KNX header.
  <p>
  On unsupported version,
  {@link ClientConnection#close(int, String, LogLevel, Throwable)} is invoked.
  
  @param h KNX header to check
  @return <code>true</code> on supported version, <code>false</code> otherwise