itch.io

What amber said, I just didn't know the solution to people who didn't have an account when they purchased it. 

That seems to be one of the only logical answers at this point.

If you haven't tried already, you could refer back to your email for the email you get for purchasing the game and continue from the download page provided there, or download the itch app and download from there, although I have a feeling you've already tried all of that. I'm sure the developer will fix the problem soon.

Edit: Im glad it worked for you, Scratch the mac problem, I hope everybody else has the problem resolved. 

What device are you on? 

You could try uninstalling the game first if you haven't already, but I have a suspicion that everybody who can't get the update even when reinstalling are all on mac. Then that's just a problem the developer has to fix.

You only need to redownload the game, as long as you know how to do that the update should be there.

As long as you guys bought the game with an account, you have full access to downloading the game again from the Itch website. At the top of the main page for the game, there's an option to download it. You can also easily navigate to your account and see your purchased games to download them again, and the update should be there once you re-download.