Using the graph API you can create a new Group Event /groups/{id}/events/{id} however because it's in a group, you're unable to set the Organizer of the event because it will always be the group it's self.

This leaves the only 2 people that can change the 'meeting options' (via a link in the calendar appointment)
- Organizer - This is the group itself (the group doesn't have a login - so it's not an option)
- The Owner - The account who run the API call to create the event. If this is a service account, then this isn't an option.

When creating an event, or updating one, we should be able to set who is a presenter or attendee of the event.

GraphAPI/Office 365 Rest API, please add support for notifications/subscription on Exchange RoomMailBox in delegated mode.

In delegated API permission mode, we are able to get events from RoomMailBox calendar but not subscribe for notifications (webhooks) on events changes
Each time we tried to create notification channel we got :
"error": {

  "code": "ExtensionError",

  "message": "Operation: Create; Exception: [Status Code: Forbidden; Reason: Access is denied. Check credentials and try again.]",

  "innerError": {

    "request-id": "XXXXXXXXXXXXXXXX",

    "date": "XXXXXXXXXXXXX"

  }

}

Moreover, in Exchange, we have full access on RoomMailBox by using user account we used on delegated mode (user account impersonated). Push notifications channel subscription works with EWS.

If we try it by using Application permission mode, everything is OK.

Could you confirm that you support RoomMailBox (actually it seems you just support UserMailbox & SharedMailBox) calendar events notifications in delegated API permission mode ?

I need to restore events from a user calendar through MS Graph API without notification sent to the attendees. The problem is that when the event is created, it automatically sends an email to all attendees, whether it's old or new event. I want to just create the event without any email send. I also tried to add a ResponseRequested=false and responseStatus=None properties, but it's do nothing.
I'm unable to find any option how to control this. Create Event should include a Boolean to enable an option to 'send notifications to attendees' if its false then it will not send calendar invite to attendee otherwise send.

We are integrating Microsoft Graph API events with our Application. We noticed that the Graph API covers almost all basic functionalities for a single event like create, updates, delete, respond to an event. But when it comes to recurring events, it lacks some basic functionalities like update this and following recurring events. 

For example, If I have created a recurring event A from 1st July to 15th July at 10 pm to 11 pm and if I wanted to update the event A timing, from 9th July onwards till the end of recurrence at 9 am to 10 am, I don't have such option available in Graph API.
For verification purpose, we had connected to Microsoft support and asked the same question. He had suggested an alternative, in which I can short master event and create a new event for the following occurrence with updated time. But it triggered an email for each operation (total two emails triggered). 

This one of the most critical projects for us, we can't accept and release this project with such alternative solution that leads to emails. I would request you to provide the functionality to update this and following as soon as possible, possible within a month.