Hi sorry if this is a stupid question, but ive searched and cant find the answer. When reading some ECU's the info is as follows

HW number
SW number
SW Upg number

HW and SW are obvious but what does SW upg mean, im thinking its the newer sw version for that hardware number, but how is that info on the ecu, cause if the ecu manufacture already had the updated software why didnt they just put it on the ecu in the first place ?

So if i read ecu and got following

HW: 1234
SW: 111
SW upg: 222

And i have file that is sw 222 is this ok to use ?