Currently there is no API to share calendar with another in user. This is possible with O365 WebApp and Outlook client. Please enable this through API also

It would be nice if the graph API supported a move event API, akin to:
https://graph.microsoft.com/v1.0/me/move/calendars/{id}/events/{id}/calendars{id}

For reference Google already provides this functionality:
https://developers.google.com/calendar/v3/reference/events/move

Update Event should include a Boolean to enable an option to 'send notifications to added or deleted attendees only' that will stop notifications going out to all meeting attendees when the only property that has been modified is attendees. This is causing an issue where people are getting dozens of unnecessary notifications when a meeting owner adds or removes attendees using the API or via a connector (ex. Flow).

When retrieving a list of occurrences for a recurring event (/me/events/{id}/instances), the result is lacking some critical data regarding exceptions. In particular, we need to know the original date/time of an exception, so that we can match it with the original occurrence. Also, there is no information at all about deleted occurrences.

Would be great if we were able to give 3rd party applications just the right to Write in to the users calendar without being able to read the users meetings. For this a simple free-busy permission would be great as well.

Then we can have calendar functionality without giving away data to other vendors.
As calendars can contain sensitive information that you are not in control over (you could get an meeting invite from someone else with sensitive information).

Graph API : How can we Audit mailbox access by Application Permission AD apps that have been granted admin consent. We are logging client-request-id, request-id, timestamp and x-ms-ags-diagnostic from the HTTP response headers of Graph but we have to reach microsoft to get details of these calls.

For an Azure AD/Office 365 admin, Graph API audit logs should be available in Security and Compliance section.

The Places API returns geoCoordinates, but does not support spartial OData queries

Microsoft Flow and Logic Apps currently support the OnUpcomingEvents endpoint. Is it possible to access this functionality from an application (not Logic App or Power App) registered in the Azure portal?

I am building an integration in our application, and want to trigger some business logic based on when an event is about to begin, but relying on Flow etc is not an option. Can this be accomplished through some sort of subscription?

Some info I found on the endpoint:
https://github.com/toddkitta/azure-content/blob/master/articles/connectors/create-api-office365-outlook.md#on-event-starting-soon

I need to cancel existing events via API.

The current stable version of Graph API does not allow to cancel any existing event, and you cannot update the isCancelled property, so the only option is to delete the event.

The cancel method is in the API beta version, but is seems it takes YEARS for the beta versions to be published as stable.

enable this endpoint https://docs.microsoft.com/en-us/graph/api/calendar-getschedule?view=graph-rest-1.0&tabs=http for personal accounts as well.

Messages API endpoint allows a query parameter $search to filter messages based on text. The same for Calendar API would be tremendously useful.

Would like to have a notification for when a users free/busy changes. Today we can do this with EWS FreeBusyChanged.

We have a pair of business workflows which have been for 10+ years been creating calendar items via the deprecated EWS API's. When moving to Exchange Online there is no like functionality.

Scenario 1) Corporate calendar for all employees - all-day calendar items that are free with no notifications

Scenario 2) faculty schedules are exported out of our ERP system and loaded via EWS API's to the faculty member calendars.

Please implement API to get a list of equipments on the same way as /findRooms !

Would like to get a notification (web hook) for when a users OOO status changes. Ideally would like to display OOO status in our 3rd party app. Today we poll at a regular interval, but would like to be notified of OOO changes.

findMeetingTimes does not consider attendee events categorised as 'Working Elsewhere' as unavailable for meetings.

This makes scheduling face-to-face meetings when some attendees may be working offsite impractical.

Please provide an option for findMeetingTimes to consider 'Working Elsewhere' as unavailable.

The /findRooms API states: "You can get up to the first 100 rooms in the tenant". Could you please add standard Pagination, to get past this limit?

I tried /findRooms?$top=1000&$count=true but I am not able to make these query parameters work. In addition, I now understand that the API doesn't currently support things like $top or $skip.

Make it possible to schedule every other week or every other month.