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.
Side question: Are there any limits to number of accounts that can be delegated to a single user ?
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/ .