Sometimes the notes in a new update to Xcode are pretty foreboding. Latest one updates for:
iOS 11.2 (current is 11.1.2)
macOS High Sierra 10.13.2 (current is 10.13.1)
Looks like os updates are imminent....
Edit: iOS 11.2 is out now. #ThatWasQuick
I think they actually stay late to re-break old ones and create new ones, personally.