From the documenation of the NotificationManager in Android:
public void notify (int id, Notification notification)
Post a notification to be shown in the status bar. If a notification with the same id has already been posted by your application and has not yet been canceled, it will be replaced by the updated information.
it will be replaced by the updated information.
I don’t want the old information to be replaced, I want both notifications.
NB: each notification has its own id:
notificationManager.notify(0, notification);
notificationManager.notify(1, notification);
How to do this?
Stack your notifications
If your app creates a notification while another of the same type is still pending, avoid creating an altogether new notification object. Instead, stack the notification.
A stacked notification builds a summary description and allows the user to understand how many notifications of a particular kind are pending.
http://developer.android.com/design/patterns/notifications.html