A method of updating safety-related software in a people conveyor system, particularly in an elevator system, wherein the method includes carrying out a predefined interactive activation operation protocol comprising the steps of: - providing an updated version of the safety-related software; - storing the updated version of the safety-related software in a first memory section of a safety unit of the people conveyor system, the first memory section being an inactive memory section that is not used for executing control of elevator operations; - connecting a service tool including a display and an input tool to the people conveyor system; - displaying an inquiry whether to accept the update on the display and inquiring an input indicating whether to proceed or to abort the software activation procedure, - sending a signal "accept" to the safety unit if an input indicating to proceed has been entered via the input tool; - after the signal "accept" has been received by the safety unit, waiting for a predetermined period of time to receive a signal "switch on" indicating that a software update activation switch permanently associated with the people conveyor system has been operated; - in case the signal "switch on" is received within the predetermined period of time, waiting for a confirmation indicating that the software activation procedure is to be started to be entered via the input tool within a predetermined time expectation; - in case the confirmation has been entered within the predetermined time expectation, activating the updated version of the safety-related software; and - in case of successful activation of the updated version of the safety-related software, overwriting an existing version of the safety-related software in a second, active memory section of the safety unit and controlling the operation of the people conveyor system based on the updated version of the safety-related software. - providing an updated version of the safety-related software; - storing the updated version of the safety-related software in a first memory section of a safety unit of the people conveyor system, the first memory section being an inactive memory section that is not used for executing control of elevator operations; - connecting a service tool including a display and an input tool to the people conveyor system; - displaying an inquiry whether to accept the update on the display and inquiring an input indicating whether to proceed or to abort the software activation procedure, - sending a signal "accept" to the safety unit if an input indicating to proceed has been entered via the input tool; - after the signal "accept" has been received by the safety unit, waiting for a predetermined period of time to receive a signal "switch on" indicating that a software update activation switch permanently associated with the people conveyor system has been operated; - in case the signal "switch on" is received within the predetermined period of time, waiting for a confirmation indicating that the software activation procedure is to be started to be entered via the input tool within a predetermined time expectation; - in case the confirmation has been entered within the predetermined time expectation, activating the updated version of the safety-related software; and - in case of successful activation of the updated version of the safety-related software, overwriting an existing version of the safety-related software in a second, active memory section of the safety unit and controlling the operation of the people conveyor system based on the updated version of the safety-related software.