What's in an update? My Samsung Galaxy S2 just updated to version I9100XWKI4. Is there a place where I can see what's in that update? And in the ones before that?

All I could find was a blog post from a site that shows how to root the device. Isn't there an official change log somewhere?
You can look at the Google Changes for each release of android, but this device uses Samsung TouchWiz. This release contains the Google changes, plus the changes that Samsung made. I do not know of a "change log" page that Samsung has.

I read that this version is the official Gingerbread 2.3.5 release of Android TouchWiz. But also, if you use a USB Jig, that it breaks the that functionality.