Report all disconnections/failures clearly in the app
Some device disconnections/failures will immediately show in the app via a change in the icon for the relevant room and changes to the reporting in the climate chart. However other devices are for some reason set up to fail quietly.
For example an extension kit controlling the boiler can disconnect and the user will not find out until they figure out that the heating isn't doing what it should. Each individual room will report that everything is working fine, but eventually it will become clear that the room isn't heating up when it should be.
If a room is calling for heat via a device that is disconnected, this should be reflected in the room information. It doesn't make sense for the room tile to say the room is heating up, when Tado knows that this message hasn't got through to the boiler because of another device failure.
I'd also suggest that push notifications should be available for disconnections, especially for items like an internet bridge or extension kit that can bring down the entire system. If a single radiator valve stops working it might not need to be responded to urgently, but if my entire heating system is down I'd like to know about it ASAP.