On Exchange/O365,can a single user subscribe for push notifications (using EWS) from a multiple users ? I know this is possible using impersonation but would like to know if we can achieve this using delegation. If yes , what would the request look like ?
Side question: Are there any limits to number of accounts that can be delegated to a single user ?
Thanks
You can but they need to separate subscriptions eg you can't create a single Push subscription that subscribes to folders in different Mailboxes (eg the Inbox in Mailbox 1 and Mailbox 2). You can create a separate Push subscription against any folder in any Mailbox you have access to (eg Subscription 1 subscribes to the Inbox in Mailbox 1 and subscription 2 subscribes to the Inbox in Mailbox 2), and you can create a subscription that subscribes to multiple folders within one mailbox.
No but there are throttling restrictions that control how many Mailbox you can connect to concurrently as well as how many you can create subscriptions against https://blogs.msdn.microsoft.com/exchangedev/2011/06/23/exchange-online-throttling-and-limits-faq/ .