A center configured to communicate with an OTA master configured to control software update for an electronic control unit mounted on a vehicle, the center comprising includes one or more processors configured to generate a distribution package including update data of software of a target electronic control unit, first information, and second information. The first information is referenced by an external device connected to the vehicle by wire when the external device updates the software of the target electronic control unit via an in-vehicle network. The second information is referenced by the OTA master wirelessly connected to the center when the OTA master updates the software of the target electronic control unit via the in-vehicle network. The one or more processors are configured to transmit the distribution package to the OTA master based on a request from the OTA master.