My app keeps track of users' calendar events via Microsoft Graph API. My database records each synced event's ChangeKey, which helps my app determine whether a event has changed and should be processed by business logic.
I also subscribe to the change notification API so that my app doesn't have to poll often.
What I found out lately is that whenever the user dismisses an event's "reminder" via Outlook (via the Outlook reminder popup), which is a very common thing to do as Outlook puts all calendar events on reminders automatically, the Graph API would send out change notification on that event.
That would have been fine – except that the event's ChangeKey actually changes, even though nothing material about the event has changed (date times/subject/body etc). Since my app uses the ChangeKey property to compare events, the business logic triggers unnecessarily.
Is this normal behavior and doesn't that nullify the practical purpose of ChangeKey? Is there any workaround other than giving up the use of this property, and instead manually check for the equality of each meaningful field for event equality?
