The Apple iPhone X will only show lockscreen notifications with actual content when it knows you are the one who is watching and if it's somebody else, they will only see the notification source, but not the notification content itself (which might be sensitive).

The future also comes with iOS 11 to earlier iPhones, but it's slightly modified: since you do not have Face ID on those earlier models, you can go into settings and enable showing notifications with content / preview only when the device has been unlocked.

NO LONGER IS EVERYONE ABLE TO SPY ON YOUR IPHONE LOCKSCREEN NOTIFICATIONS.

This replicates settings that have been implemented in Android notifications long time ago: you can set Android lockscreen notifications to appear with content on or with the content hidden, while the second option was up until now completely missing from iOS. What iOS did offer up until now was two options, which were either to show full lockscreen notifications with content or not show lockscreen notifications at all (to be perfectly exact, the feature was available in Mail and Messages, but nowhere else).

Does iPhone X only shows the notifications if it sees your face or is there any otherway of it finding out if you are the person viewing it? @MusicX

It will show only program icon and word notification if you don't be recognized with Face ID, but shows full notification if you do. @Seb23100

That's really cool, too bad I can't afford it