A vehicle may receive a software update to be installed to a vehicle electronic control unit (ECU); perform compatibility testing for vehicle ECUs according to tokens from the vehicle ECUs indicating respective software version levels of the vehicle ECUs to determine a compatibility result; and switch the software update into active use on the vehicle when the compatibility result indicates an allowable configuration of software version levels. A vehicle ECU may receive tokens from other of the vehicle ECUs indicating respective software version levels of the other vehicle ECUs; determine whether the ECU is the most up-to-date ECU based on the tokens; and if so, determine a compatibility result indicative of compatibility of the version levels, or otherwise, receive the compatibility result from the ECU that is the most up-to-date.