I have a mesh network formed by three M5 V3 Decos working without issues. Two units work as satellites and in both I can see the "Connection Preference" option where I can select to which Deco unit to connect (or just select Auto), the three units are M5 V3 with Firmware 1.7.4 (latest update).

I recently adquire a new unit M5 V3 to add it to my network but this unit for some unkown reason has Firmware 2.5.10 (latest update) and this new unit doesn't show the "Connection Preference" option so I can't select to which unit to connect and this is causing issues because it's connecting to another unit with a waek signal. I need the "Connection Preference" option because I need to select the correct units to connect because of my home configuration.

I tried to set the new unit as the main Deco but that causes my other units to fail in "Conecction Preferences", I reset the new unit several times and updated the firmware to the latest version (of all the units) but I keep the same issue. I don't know why if is the new unit is the same model has a different Formware Version and why is not showing the "Connection Preference" option.