You can turn off game notifications in your device settings.
For iOS devices:
1. Go to Settings -> Notifications.
2. Find Cradle of Empires in the application list and select it.
3. Go to Notifications (the right side of the screen) and turn off Allow Notifications.
4. Sounds, Alerts and Badges can all be turned on or off individually.
For Android devices:
1. Go to Settings and choose Apps.
2. Scroll through the list of apps and find the app.
3. Touch the “Show notifications” check box so there’s no check mark in the box.
For Amazon Kindle devices:
1. Go to the Settings
2. Tap Sound & Notifications
3. Choose App Notifications, and then select an app from the list to allow the app to appear in the notification tray or play a sound when a notification arrives for that app.