The following instruction of this topic will guide you to Disable Memories Alerts on iPhone and iPad in iOS 12. You might no longer want to have an announcement saying something like this "You have a new memory". Do the same as the below steps to switch off the unexpected memories warning in iOS 12 on your iDevices.
How to Turn Off Memories Notifications on iPhone and iPad Running iOS 12
Step 1. First of all, head over Settings app on your iOS device → tap on Notifications.
Step 2. Then, tap on Photos.
Step 3. Afterward, Select Memories.
Step 4. In the last step, turn off the switch on the right of Allow Notifications.
You can also check out the option to modify the alerts under Photos Options section . You can choose to receive alerts from everyone or restrict the app to send notifications only from your contacts.
Going forward, the notification “You have a new memory” will no longer pop up from the Photos app.
Once you decide to reverse the decision, all you need to do is come back to the same setting. After that, turn on the toggle to enable Photos Memories notifications.
That’s pretty much it