I have read many articles about Exchange hybrid mode, Microsoft Graph, EWS, but it is not clear: Is it possible in a completely offline configuration (on premise AD, Exchange 2016) to access/edit users' mailboxes, calendars? If yes. In what way? EWS? Ms Graph? So without O365. Is there a tutorial on this?
it possible in a completely offline configuration (on premise AD, Exchange 2016) to access/edit users' mailboxes, calendars?
So your just talking about regular exchange ? yes EWS will work for that like it has since Exchange 2007 I would start with https://learn.microsoft.com/en-us/previous-versions/office/developer/exchange-server-2010/jj220499(v=exchg.80)