How to remotely update/change game?

So this isn’t about Unity specifically, but I have a game that I don’t plan on putting on the play store, but rather just hosting on my own website. Which means I am going to need to handle update management and all that. If possible I would love for it to just check for a new version when it starts and then automatically download that, but I’d also be fine with being able to somehow like remotely switch the value for a playerpref or something that notifies players there’s a new update when they open the app whenever I make a new update. How would I go about adding this kind of “remote control” to my game?
I know you can use something like Firebase or whatever it is for mobile push notifications over the cloud but I don’t really want to have to pack all of that into my app and would rather just have a cleaner or more simple solution than that.

Unity has a web request helper that should do what you need.

Whenever the application starts up it can send a web request to ask “what’s the latest version?” and then prompt the user to update or reinstall if the versions don’t match.

That data will need to live somewhere, though. If you’re hosting on your own website you may be able to create a public API that the game calls to get that info. Otherwise, you’ll need to host a database.

If you’re distributing on itch.io, you might be able to use their API to fetch the latest “published_at” date and do something with it.