Why does Skitch expire when a new version is available?

I downloaded Skitch just a week ago and instantly fell in love with it. So it was awfully off-putting to be told today that it's expired and I need to download a new version.

Yes, I know the terms of service say Skitch can do this. But I'm on a very limited broadband plan -- I regularly surf with images turned off to save bandwidth -- so it's hard to justify that bandwidth to myself no matter how much I adore it. Especially when I don't know what the file size will be so can't work out whether I've got enough bandwidth spare in this billing period!

I'm particularly reluctant to upgrade when I don't know how often I'll have to upgrade in future. On the other hand I might be really excited about upgrading if I knew what new features the new version has, but I can't find a thing about it even on the blog.

The other thing is that... well, with Skype there was a time when the newest version gave me serious compatibility problems. But it was easy enough with them to track down an older version and reinstall that, and I kept praising Skype to the heavens. If there hadn't been an older version available, I'd have been completely stuck -- and would have complained to everyone in hearing. So by forcing us to upgrade, it seems like you're putting all your eggs in one basket and burning your bridges behind you.

Anyway, if the upgrade's worth while and I won't have to do it too often then I'll get it, because I really do like the program. But I'd much rather know something about it before I do, and I'd *much* rather have been given the choice of when to do it.