First we are happy to report that this can work. Your FileMaker iOS SDK application can register for notifications and report you the device token. This device token is needed to send push notifications to the device. Push notifications can show a message to user, set the app badge or transfer data to the app.
First please review our documentation for the UNNotification functions. When you add the MBS Plugin to the project, please also add our MBSInit framework. You may need to split both to only include the arm versions in the final app to run on a device.
After your app launched on a device, you may be asked to allow notifications. This happens only if MBSInit framework is loaded and triggers the early initialization of our plugin. The function UNNotification.RemoteNotificationsDeviceToken returns you the device token as a long text with hex encoding. If something goes wrong, you get an empty text there and the function UNNotification.RemoteNotificationsError will give an error message, e.g. that this is not available in simulator.
You can check permissions with UNNotification.IsRegisteredForRemoteNotifications later. The new functions UNNotification.AuthorizationGranted and UNNotification.AuthorizationError let you know about whether you can work with notifications. But most likely you will check with UNNotification.NotificationSettings directly for what is available or allowed. The user can for example allow you badge changes, but not popups.
Let me know if you like to try this and need assistant. You should be able to get notifications to show messages to the user, launch the app and trigger scripts. Even the sending of notifications to devices should work via MBS Plugin by using CURL functions to talk to Apple's web service.