A new feature for privacy was added in build 10149 of Windows 10 Mobile. This is the option to leave the information of their hidden notifications, meaning you receive notification but not see its contents.
OS will now offer users the app by app option of hiding the content from notification messages from the lock screen, meaning some-one who picks up your sleeping phone could for example see your facebook messages, but not the contents of your whatsapps.
Now you can choose the ” keep private notification when the screen is locked . ” This will cause when your screen is locked (password) information in a notification is displayed. This is an interesting feature for those who do not like to block notifications with the locked screen, but would like to block the content of notifications.
One example is for applications such as whatsapp: Despite being notified, the person can not see what the content of the notification is not unlock the device.