getting system notification

dates stored in Contacts pop up in Apple Notifications even when Contact is not running.
I know how to do it in Xojo when an app is running, but I would like to have Apple Notifications pop up when my app is not running.
Any suggestion how to do it?

Thank you.

I think you would need a helper program… Once your program is closed, it’s closed…

You can schedule NSUserNotifications to show up at any time.

Sorry, I did not specify that I’d avoid use of plugings. Thanks anyway.
And thank you, Shao.

Christian gave you the way to do it. If you don’t want his plugin, then do the learning yourself as to how to use NSUserNotifications.

Actually, as Shao Sean quite rightly noted, once the app is closed, it is gone for good and cannot process any message. A while ago, Ulrich Bogun posted a small project that reads all system messages. Unfortunately, I cannot locate it again.

It would make sense to use a small helper running in the background, with no icon in the dock which monitors contacts.

To all: thanks for your replies. Really greatly appreciated.
Time to consider which way to choose.