"Supported" here means in the context of the mobile app. They are not supported for viewing or control in the mobile app, as you can tell by the fact that they do not show any of their current states (like on/off for a switch) or let you control them (like unlocking a lock or turning on/off a bulb). To be extra-clear, this does not have anything to do with your ability to view or control devices on the hub itself or with apps/automations you have set up.
You can use the three-lines menu in the upper right to "Hide unsupported devices" if you want to revert to the old behavior. This is a recent change made due to some people's confusion over the fact that the mobile app only showed devices it "supported," and then they thought the devices just weren't on their system at all. This is a compromise for now; you'll see fewer and fewer of these as the mobile app expands to actually support more device types.