I suspect that it takes a hardware intervention, so you can use this menu item. With your adapter it will then go without hardware intervention.
Every house in Switzerland is connected to a three-phase system. If I want to measure the voltage with a VT for each phase, this is very difficult to do. One would have to install a separate socket for each phase. The IotaWatt could not be installed so easily.
For me it would be acceptable to do without a voltmeter. I could live well with the accuracy of plus minus 5%. I only need the measurement for comparison or control and to find big consumers, for example. I do not need absolute and exact numbers.
Would it be possible to create a virtual VT while configuring the VT? This means that I can enter a voltage that is the same on all three phases and is a fix voltage, not a measured.
Unfortunately, I understand the connections at IotaWatt between hardware, firmware and software not yet. Who would be responsible for such a program change?