I mean like I have all hats on my copy and my sister doesn't.
Could it really be cuz of updates?
Has nothing to do with updates, the itch.io version doesn't support in-game purchases. all the others do.
Because I have all the hats on my PC and my sister doesn't (on her PC). We both use the itch.io version. I remember back when I downloaded mine it was like "among-us-windows-all-hats.zip" or something like that but my sisters copy isn't.