When I made the sale purchase last year, and an upgrade became available, I asked the developer about this same situation. I was told there would be a short wait, and just as stated, I was able to download the update without additional pricing.
Viewing post in Knightly Passions [1.03 version] 18+ comments
That's the thing, that's what you get for the 1 dollar tier you have to wait for a short while before the update is available to you. The people who are complaining are people who paid the old 10 dollar price (or 5 dollars during a discount) to get the immediate access. But then the price was increased and everyone who bought the old full version got kicked down to the limited version.
Yeah, also I did openly say it hoping there was a solution of "oh shoot, sorry. Here is the link since you got it early". Like I be fine like sharing I just got it, plus it being a 5 dollar thing. Maybe it is too much, and hell I will get it in a week or 2 I believe based on what I saw.
Like it is an indie game, they put a lot of work in it. I just hope there be a solution here, or "Hey yeah give 5 more dollars or wait". But again, really the only issue is just bad luck. Like I probably will decide on waiting or full price. End of the day, it isn't the end of the world or scam, just a small issue.
But I also do get where people do have bigger issues, so I do hope those people can find a solution or so.
I got it long ago, and during the sale for $5.00, and when I had this same update issue, the developer responded to me with the wait news. I believe the developer said is an itch issue. I have since received two updates. If the free update model for those buying at the sale price has been removed, it is news to me, and definitely a bad thing going forward, but he/she seemed nice about it and even said there would be a steam key for the $5.00 purchasers. I am sure he or she will examine the posts and let us know something shortly. The developer appears to be fair. Afterall, it was the sale purchases which likely provided the revenue to continue the project. I paid $1.00 so long ago, my original save files couldn't be upgraded. People like me are the reasons you can advance the story.
Additionally, I can see the link for the new update, but it does not allow me to see the files, so it seems to be pending. Like I said, the developer said it is an itch issue. Just give it a little more time.
Also it's probably not something on their end that went wrong, probably more to do with Itch.io's way of storing what was paid for products.
So the devs probably (justifiably so) increased the price and then Itch just goes "We don't store what product you purchased just how much you paid on what projects. So since you paid 5 bucks during a 50% off you get access to everything up to 10 dollars, regardless of how the products price develops."