With the leak of Windows 8.1 build 9385, a new setting was added to the build that allowed for applications to display alerts on the lock screens. At the time of the leak, this feature was not functional as there were no applications that you could select to test out the option.
Step in Bavogames who has found a way to enable this feature and has demoed it in the video above. The video is a walkthough of the feature and also tells you how to enable it on your local machine if you wish to test out this feature.
The feature works exactly as you would expect. It allows you to select an application and then display the pop-up notification on the lock screen. While not a groundbreaking feature by any means, it will certainly be useful for those who have been wanting a feature that will allow then to view selected notifications on the lock-screen.
This is one of the many new features that will be coming to Windows 8.1 and we will get our first official look at the platform at BUILD where Microsoft will be releasing a public preview of the platform.
Source: YouTube