A transformation device installed in a vehicle, comprising: a transformation section that transforms data transmitted from a first control device in a first communication protocol to data in a second communication protocol; a transmission section that transmits the data transformed by the transformation section to a second control device ; a detection section that detects an update of at least one of the first control device or the second control device by detecting a novel signal from the first control device or the second control device; and a control section that: determines whether the novel signal is not an erroneous signal and whether no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, in case it is determined that the novel signal is not an erroneous signal and no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, obtains confirmation from a user as to whether the first control device or the second control device has been updated; and in case an update of at least one of the first control device or the second control device is confirmed by the user, changes a mode of the transformation by the transformation section . a transformation section that transforms data transmitted from a first control device in a first communication protocol to data in a second communication protocol; a transmission section that transmits the data transformed by the transformation section to a second control device ; a detection section that detects an update of at least one of the first control device or the second control device by detecting a novel signal from the first control device or the second control device; and a control section that: determines whether the novel signal is not an erroneous signal and whether no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, in case it is determined that the novel signal is not an erroneous signal and no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, obtains confirmation from a user as to whether the first control device or the second control device has been updated; and in case an update of at least one of the first control device or the second control device is confirmed by the user, changes a mode of the transformation by the transformation section . determines whether the novel signal is not an erroneous signal and whether no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, in case it is determined that the novel signal is not an erroneous signal and no previous signals from the first control device or the second control device are being propagated through the network during the determination whether the novel signal is not an erroneous signal, obtains confirmation from a user as to whether the first control device or the second control device has been updated; and in case an update of at least one of the first control device or the second control device is confirmed by the user, changes a mode of the transformation by the transformation section . <EOS>