code: public int getTangoVersion() throws DevFailed {
  
          //  Get idl for administrative device
          int adminIdl = get_adm_dev().get_idl_version();
  
          //  Check with ZmqEventSubscriptionChange command
          //  since 9.1.0 this command returns Tango release in info mode
          int version = getTangoVersionFromZmqEventSubscriptionChange();
          if (version>900)    //  Found
              return version;
  
          //  Get the command list
          CommandInfo[] commandInfoList = get_adm_dev().command_list_query();
  
          //  Check between idl and commands
          switch (adminIdl) {
              case 1:
                  return 100;
              case 2:
                  return 200;
              case 3:
                  //  IDL 3 is for Tango 5 and 6. Unfortunately,
                  //  there is no way from the client side to determine if it is Tango 5 or 6.
                  //  The best we can do is to get the info that it is Tango 5.2 (or above)
                  for (CommandInfo commandInfo : commandInfoList) {
                      if (commandInfo.cmd_name.equals("QueryWizardClassProperty"))
                          return 520;
                  }
                  //  Not found
                  return 500;
              case 4:
                  //  try if tango 8.1 (Confirm for several events)
                  for (CommandInfo commandInfo : commandInfoList) {
                      if (commandInfo.cmd_name.equals("EventConfirmSubscription"))
                          return 810;
                  }
                  //  try if tango 8.0 (ZMQ system)
                  for (CommandInfo commandInfo : commandInfoList) {
                      if (commandInfo.cmd_name.equals("ZmqEventSubscriptionChange"))
                          return 800;
                  }
                  return 700;
               case 5:
  			 	return 900;
         }
  
          //  Not found
          return 0;
      }
docs: ===================================================================