Differences in Calendar ID - Outlook REST API <-> EWS RRS feed

  • Question

  • Hello,

    We are currently developing on a new synchronization model for outlook objects.

    The new model uses Outlook REST Push Notifications to receive updates on Outlook objects instead of the EWS Streaming-Subscriptions.

    Currently we have a problem with the Calendar IDs. Retrieving Notifications on a Calendar let us receive a much more longer ID than we had already requested over the EWS and we could not associate the Notification to the correct Calendar.

    Why is this happening and is there a way to convert the longer ID to the smaller ID?

    Here a short sample:

    Outlook REST API Calendar ID:


    EWS Calendar ID:


    Thursday, October 25, 2018 12:27 PM