A method of updating at least one security certificate of a safety circuit of an elevator system includes: connecting the safety circuit with a communicator which is capable to communicate with a certification server; sending from the communicator to the safety circuit a security certificate update request for updating at least one security certificate stored within the safety circuit; the safety circuit sending a public key of a safety circuit security certificate associated with the safety circuit via the communicator to the certification server; the certification server checking whether the safety circuit security certificate associated with the received public key is included in a data base of known security certificates and not marked as compromised.