ATS25 Max-Decoder (SI4732)

 I write this in English so that maybe someone can give me a usefull hint.

I got some months ago my 4th ATS25: I have the very first version with a soft touch knob for tuning, an ATS25X1 an ATS25-Max and theis last the ATS25 Max-Decoder.

Basically the X1 and the Max are the same: they just have some more functions and much improved graphics compared with the fisrt ATS-25. It seems  to me that one of the two (either the X1 either the Max version) has less muting during tuning. This muting while tuning is the only aspect I do not like about this receiver. Concerning other properties I would say it's a nice toy, for easy scanning and reception without pretending too much from it.

That said: in this later version of the Harduino software I see a bluetooth option, but it does not turn on, wifi connection works pretty well, all the rest is fine. Just this bluetooth which I am not able to get working.

The software is the 4.16 Air, however, compared with the pictures available in the dedicated web page of Harduino, the receiver' screen shows another submenu, the following in the blue circle:

Apparently this works on the choices for the aerial impedence, could be that "BT" stands for bluetooth, but opening the submenu it cannot be activated. I do not see any instruction related to this also on user handbook I got from the seller.

Is there someone who has a clue about this?

Thanks and 73