The latest iteration of Microsoft’s Windows Phone will reportedly support 20 notifications per app through the Action Center, a notification hub for the mobile operating system. This function was allegedly discovered through some APIs claiming that users can view up to 20 notifications per app. Persistent notifications will also reportedly be visible for up to a week. Reports claim that developers will be given the ability to send, replace, remove, tag, and group notifications. They will also be able to provide expiry periods for the notifications.
Source: Ubergizmo