Old unity 2d question (tilemap)

I was just wondering if there is a way to add a new unity function (tilemap and package manager) to an old unity version? I can only download the 32-bit version but that means I have no package manager or tilemap option as far as I can see, and I can't find a tutorial teaching me what to do instead. Which means I can't continue making my top down rpg.
So can I add a new function to an old unity? Sorry if this is a crazy question, I'm a noob.