itch.io

I, like many others, have come here from the bundle.

You should be able to set the game to Restricted, which will allow people who own the game to download it, but will disable people who don't own the game from being able to buy it new.

https://itch.io/docs/creators/access-control

Have you looked into the Restricted access options as linked by Demonskunk? If it's possible to do so, you should really give back access to this game to everyone who purchased it previously. It's really unfair to simply take part of our purchase away without notice or any alternative than to pay again.

https://itch.io/docs/creators/access-control

Please look into the restricted option. I, like many others, bought the bundle that this was a part of. It's a bit scummy to not allow people who paid money expecting to get your game to play it because they haven't also bought the new version.