I happen to see a new format of Google Sitelinks while performing search query this morning.
Notice the layout of the links. They occupy less space but they are also aren’t as prominent as in previous layout as shown here.
Another query showed a surprising layout. The top ranked didn’t get any sitelink at all, but the site ranked below it has sitelinks using the new format!
So far I not yet found an official statement from Google regarding this update.