Push Notification Certificates let you send notifications to users of your app. They expire one year after creation and must be renewed in order to let you send in-app notifications to your end-users. One month prior to expiration, the iOS Dev Center will email a warning to your associated brand admin.
Certificates issued by Apple are for one year at a time, and a new Push Notifications certificate will be required to send out iOS push notifications via your Mobile Loyalty Apps.
If you receive an email, you can send a request to Punchh Support (click here)