Upgrade Wars

Even though different Cyber-subspecies mostly had the same goals of survival and logic, resulting in them allying together to create even stronger forms instead of fighting, (AUDIO: The Cyber Nomads, PROSE: The Whoniverse, et. al) one time traveller claimed that the Upgrade Wars were a series of civil conflicts amongst the Cybermen that were kicked off on 15 April, 2342. According to the traveller, the wars arose when two factions of Cybermen failed to concur on what operating system was best to use. (PROSE: Time Traveller's Diary)