Yes, if you're using the itch desktop app and one of the supported builds of Monstrata, then itch will download any updates automatically. c: (There are a few older builds that it will not do this for, which have been removed from the page.)
As I understand it, this is because we update the game through itch.io's assistant, butler, rather than by adding completely new builds to the page. That may be why it updates automatically for Monstrata, but may not do the same for other itch.io games where the developers have chosen not to do that.
Thank you for playing!! Let us know if you have more questions!!