Hi @Public Account ,
You can check the lifecycleUrl concepts, this is to help applications awareness on missed notifications exist, so an application can resync, only upon detection of missed ones, and not by polling delta queries which would make the solution not scalable.
You can use the below link to get more details on lifecycle notifications.
Reduce missing subscriptions and change notifications - Microsoft Graph | Microsoft Learn. This mechanism requires that you expose a separate webhook to process notifications of type “lifecycle”. In case a service missed a notification for your subscribed-to resource, you will be notified with a “missed” notification. This notification will not include the ID of the missed item; hence your application will need to resynchronize this resource.
As it is not feasible to resynchronize a resource from scratch every time a notification misses, it is recommended that you also implement delta change tracking alongside change notifications. This is documented as a best practice here: Best practices for working with Microsoft Graph - Microsoft Graph | Microsoft Learn
Please also read this blog to get more Insights on how lifecycle Notifications can be useful.
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