I am playing on Civ V from Steam on my Ubuntu (Linux) OS.
I am playing the English nation and use the longbowman with pleasure. I read on the wiki that this unit can upgrade to Gatling gun and keep its range bonus. I can't find the Gatling gun in my version of the game. The longbowman seems to upgrade to rifleman. More over, the Gatling gun need Industrialization tech which does exist on my version.
Do I need a mod/extension for this to work?