The game's story is completely unchanged.What's different in the latest version? Well, some people were getting confused and frustrated by not being able to reach Callum's path on the first playthrough and not knowing why it wasn't working. So, the newest version now adds a menu at the Talk To Callum / Talk To Oscar point, making it visible that Callum's option exists but is locked.
You can also now view the endings gallery from the options menu to check what you have and haven't reached, and to see whether Callum's route is unlocked yet. This may count as a bit of a spoiler since the endings aren't necessarily obvious from the beginning, but anyone intentionally looking at an endings list probably doesn't mind spoilers.
Webpage with proper purchase link for new version:
http://www.hanakogames.com/tcotc.shtml
With this new release I'm testing out the option from my sales provider to have all the different operating system versions for a game linked to one purchase, so future customers won't have to worry about how to get a different version if they change computers. In order to do this, we had to create a new product entry. Unfortunately this means that I can't easily issue new downloads of this version to previous customers (although if you have steam keys you already have the new version, and there's no new content so you don't really NEED the new version anyway). Side effect is that if for some reason you really wanted to buy the previous version and not this one, it still exists, so you can do that.
Anyway, none of this should matter at all to you if you've already played the game, but I wanted to keep you informed.