Systems and method for safely distributing software for electronic controllers in the refrigeration container industry, and also communication systems primarily for electronic controllers related to refrigeration containers in which fast software distribution in container controllers is achieved by introducing a buffer memory in the communication system, which buffer memory includes a new container controller software version. The communication system distributes the new container controller software version by a communication device, to receiving communication systems where the new software version is placed in the buffer memory. As a result, it can be achieved that software distribution starts automatically as soon as only one communication system includes the new software version, this software version will in a very short period be spread into all container controllers, e.g., on board a ship or in a container yard.