As some are aware, Gamejolt stopped supporting the game and took it down.
In my case I got a key for my old Purchase with download files.

However that download only gives me access to version 1.39. I can see here on Ithc.io that there have come more updates since then, and was Wondering if I have to buy the game again to get access to the new updates, or if something can be worked out?

I can Answer this question Myself now, and can say it is possible, for anyone else who came across same situation as me.
I suggest, getting contact to Shades himself or the Shady Corner Assistant through Discord.
Breezy the Assistant was very welcoming support, and after sending what they needed to know about my old Purchase, they got back to me the Day after and offered a solution to my Situation.

Happy Ending \(ouo)/