Do i still have to buy newer versions even if i bought the paid version of the game
For this project - yes. It's due to the fact that this is a reward for my patrons of 6$ or more on my Patreon page - they contribute monthly to project development so it's only fair.
On the plus side, the current "latest" version will become the public version with each new release.
So if you don't want to spend you can just play the free version when it's updated.