Hi, I have a X50-5G used as modem and router plus 3 X50 to extend the wifi network.

Recently, I tried to connect an old iPhone 4S (ios 9.3.6) and use it as a Spotify / Deezer server on a speaker. The connection to the WPA2/WPA3 Personal main WIFI was not possible (iPhone too old maybe) so I've created a WPA2 guest network. It works fine but every 15 to 30 minutes I receive an alert telling me that "a new device" has joined the network. It even uses the name I gave to the iPhone, which proves that although it recognizes it, it still considers it as "new". How can I stop those endless notifications?

Please note that the device runs on ios 9.3.6 so there is no "Private Address" feature and this only happens on for this device. Thanks.