Apple has released iOS 11.2.1 and tvOS 11.2.1, with bug fixes and minor changes including restoration of remote access to shared users of the Home app.
The fix to both iOS and tvOS is a restoration of shared Home access, after an issue with HomeKit posed a threat to smart door locks and garage door openers. At the time, Apple implemented a temporary fix by disabling remote HomeKit access to certain users -- which it said would be restored in a future software update.
The update is 68.7MB on an iPhone X, and is available through the normal Software Update function in the iOS Settings menu. Similarly, fourth generation Apple TV or Apple TV 4K owners can get the update through the Settings menu on that platform.