Facebook is testing new mobile features, including sound alerts and an option to reply directly to comments to an original post, as the social network looks to boost its use among smartphone users.
The company said the new features are still in the testing stage and will not be immediately available to everyone.
The sound alert occurs whenever a user receives a notification, such as when someone likes or comments on one of their post. The feature could potentially cause annoyance among heavy users.
Facebook also is trying out a reply option for comments posted to Timeline.