Don't update large files

I am working on integrating sparkle into an app that contains a very large, immutable data set (>4GB). We obviously don't want to re-download the data set each time we release an update to the app. I've been researching delta updates, and while it seems like this would work, it looks like they only work with binary patches (is this correct)? If so, we would need to provide delta updates for each possible upgrade path (ie. 1.0 to 1.1, 1.0 to 1.2, 1.1 to 1.2, etc).

Is there anyway to use delta updates without going the binary route? Ie, merge the two bundles instead of deleting the old one and replacing it with the new one?

Or maybe a way to specify a file that should be moved over from the old bundle to the new bundle before the old bundle is deleted?

Thanks for any direction on this!

Kelly