Abstract: A method for automatically changing software version in a computer system comprising a plurality of stations that are to execute in parallel a plurality of replicas of the same software. A series of successively messages, communication protocol, between a master station and each slave station required for initializing and making necessary preparations at each of the slave stations prior to the version-change actual issued. In this way, without human intervention, all of the stations ensure that do restart after receiving the version-change order do indeed all restart actually executing the new version.