A device can be removed.
If the device type is deleted, the devices are not automatically deleted. They are still displayed in the Device stats widget but can only be reached via the Things API.
You are assigned to the Manager role or higher.
Proceed as follows
In the device type overview, click the Settings icon of the device type of which you want to change the settings.
→ The settings of the device type are displayed.
Click the Remove button next to the device type name.
→ The confirmation dialog is displayed.
Click the Confirm button to remove the device type.
→ The device type has been removed.
If you want to delete a device type with all its devices, you have to delete the devices beforehand as they are not automatically deleted.