Are you sometimes losing your WiFi connection without you noticing it? Data Sense only notifies you when you are nearing your data plan limit, which is rather late. Mobile Data Notifier notifies you directly when you start using mobile data or when you start roaming. You can also get notifications in case you are using mobile data and the current network usage is high (in-app purchase required). By this you can easily keep an eye on your mobile data usage and avoid unexpected charges!
Mobile Data Notifier is now available for Windows Phone 8.1 in the Windows Phone Store.