Broadly speaking, embodiments of the present technique provide methods, apparatuses and systems for operating a server in communication with a network-attachable electronic device, comprising: storing, in storage accessible by the server, a device registration and a registration lifetime value for the device; receiving at least one message from the device; analysing the message to derive a confidence modifier associated with a message type associated with that message; applying the derived confidence modifier to a calculation of a confidence score for the device; and responsive to the calculation, determining whether a stored registration lifetime value for the device is to be adjusted based upon the confidence score.