Provided is a method involving obtaining an identifier at a control unit of a compartment system having compartments provided with respective locks and respective lock control units that are configured to communicate with the control unit; obtaining information indicating that one compartment has been closed, and causing storing of the identifier in the lock control unit assigned to the compartment. Also provided is a method comprising detecting, at a lock control unit assigned to a compartment of a compartment system comprising a control unit and compartments provided with respective locks and lock control units configured to communicate with the control unit, that the compartment has been closed; transmitting a piece of information identifying the lock control unit to the control unit if it has been detected that the compartment has been closed; obtaining an identifier from the control unit; and storing the identifier in the lock control unit.