I think you're better off doing it on steam as updates usually get pushed there a bit faster than itch.
Hi ji19 and Rika! Apologies for the late response!
Itch.io will be getting updates, but not as fast as the Steam counterpart because it takes a lot of time for us to upload the whole game in their server.
But as of writing, Itch.io has the latest 1.0.3a version that Steam also has. :)