After some profiling with FileMon:
The latest client doesnt patch the diffs anymore. It still responses to the MapPatches packet (0xBF, subcommand 0x18) sent by RunUO with loading all the Diff-Lookup-files (stadifL, mapdifL files) but after that, it doesnt go further with using the index and data files (though, unlike verdata.mul, they're still opened at every client startup). It just doesn't display them
As a real fan of the diff patch mechanism (easy deployment, small size, runtime patching) I really hope this is a temporary change so the diffs don't interfer with the 'new' maps and they'll be activated with one of the following updates during the next weeks. But perhaps this was done because KR wouldn't support diffs at all, which would make them useless for EA.